Discussion on welding positioner types and series

Zheng Yongqiang, Tianjin Engineering Machinery Research Institute

1 Introduction

In our country, welding The positioner has quietly become an indispensable equipment in the manufacturing industry, and is classified as a welding auxiliary machine in the welding field. In the past ten years, this product has achieved great development and has been widely used in my country's construction machinery industry. In terms of model series and varieties and specifications, there are about ten series and more than a hundred varieties and specifications that have been launched, and a small industry is forming. The author hopes that this product can develop healthily, orderly and rapidly; companies can compete on an equal technology basis. In our country, and even internationally, there are inconsistencies in the basic concepts, types and classifications, and main technical parameters of welding positioners. There are even some dimensional confusion problems, and the author hopes to have a unified understanding.

In people's eyes, the welding positioner may be considered an insignificant product. However, internationally, there are more than a hundred series including products with various functions. Technically, there are ordinary types; there are gapless transmission servo control types; the rated load range of the products reaches 0.1kN ~ 18000 kN. It can be said that the welding positioner is a product with many varieties, high technical level, and complete development of small, medium and large sizes. This article hopes to give him a proper technical positioning.

2 Introduction to the development of welding positioners at home and abroad

This article is not a monograph on the development of welding positioners at home and abroad. Based on the above research purpose, this is only an introduction. Generally speaking, most manufacturers that produce welding manipulators, roller frames, welding systems and other welding equipment produce welding positioners; most manufacturers that produce welding robots produce welding positioners for robots. However, companies with welding positioners as their leading products are very rare. Severt Company in Germany, Aroson Company in the United States, and Tianjin Dingsheng Engineering Machinery Co., Ltd. in my country are relatively typical companies that produce welding positioners. Germany's CLOOS, Austria's igm, Japan's Panasonic Robot Company, etc. all produce welding positioners with servo control and robots. The following only introduces the positioner type, first main parameters, etc.

2.2 German Severt Company

This company mainly produces 8 types of products, 7 of which are welding positioners. Each type of welding positioner, according to its function, includes four types of products: basic type, speed-regulating type, CNC program-controlled type and robot supporting type.

⑴S10 type, including 4 product series including S10.1, 2, 3, and 4 types. Namely: ①L-type double rotary type, L-type double rotary lifting type; ② L-type double rotary-tilting type, L-type double rotary-tilting lifting type; ③2×L-type double rotary type, 2×L-type double rotary lifting type Type; ④2×L type double rotation-tilting type, 2×L type double rotation-tilting lift type.

⑵S20 type, including S20.1 and 2 type product series. That is: ① single-seat single-rotation type, single-seat single-rotation lifting type; ② C-type double rotary type.

⑶S30 type, including S30.1 and 2 type 2 product series. That is: ① Vertical single rotation; ② Vertical single rotation double station.

⑷S40 type, including 7 product series including S40.1, 2, 3, 4, 5, 6, and 7. That is: ① Two-seat single-turn split type; ② Two-seat head and tail single-turn type; ③ H-type two-seat double-turn type; ④ Two-seat head and tail single-turn tailstock mobile type; ⑤ Two-seat head and tail tilting tailstock mobile type; 3-seat single-rotation type; ⑦ single-seat rolling ring single-rotation type, double-seat rolling ring single-rotation tailstock mobile type.

⑸S50 type: including S50.1, 2, 3, 4, 5, 6, 7 types, 7 multi-axis (degrees of freedom) product series. That is: ① Vertical 3-axis single-rotation double-station type; ② Vertical single-rotation double-station 2×tilt-rotary type (5 axes); ③Vertical single-rotation multi-station 2×L-type double-rotation type (5 axes); ④ Vertical single rotary double station 2 × L-shaped double rotary tilting type (7 axes); ⑤ Vertical single rotary double station 2 × double seat single rotary (3 axes); ⑥ Vertical Single rotary double station 2×C type double rotary (5 axes); ⑦Vertical single rotary double station 2×Horizontal single seat single rotary (3 axes).

⑹S60 type: including S60.1 and 2 type product series.

That is: ① Tipping--rotary type (0°~90°); ② Tipping--rotating type (±90°).

⑺S70 type: including three product series: S70.1, 2 and 3. That is: ① Vertical multi-station 4-axis (4 degrees of freedom) single rotation; ② Vertical multi-station 2×tilt-rotary (6 degrees of freedom); ③ Vertical 4-station vertical 4-axis single rotation turn around.

The above ***33 product types, each type includes products with the above four functions, equivalent to 132 product series. The rated load is 100dN～10kdN.

2.2 American Aroson Company

The welding equipment produced by American Aroson Company includes welding positioners, manipulators, roller frames, etc., which can be called the best in the world. The main types of welding positioners produced by this company are tilt-rotation type, tilt-rotation lifting type, two-seat double rotation type, two-seat single rotation type and two-seat single rotation lifting type. Its carrying capacity ranges from 11 kg to 1810 tons.

⑴ Manual double return type. C series, models C1000, 2000, 4000. Carrying capacity is 25 pounds to 4,000 pounds.

⑵Small tipping-rotating type. LD series, models LD 60N, 150N, 300N, with load-bearing capacities of 132 pounds, 330 pounds, and 660 pounds respectively.

⑶Tilt-rotary type, tilting angle 135°. D, HD series, load capacity 314 pounds to 70,000 pounds

⑷Tilt-rotation (pin change) positioning lifting type, tilting angle 135°. AB series (30 ~ AB1200), load capacity 4300 pounds ~ 120000 pounds.

⑸Tilt-rotation (rack and pinion) stepless lifting type, GE series, tilt angle 135°, model (GE25~GE3500, load capacity 2500 pounds~350,000 pounds.

⑹Tilt-rotary type, tilting angle 90°, G series, G400～G4-MEGA type, load capacity 4000 pounds～4 million pounds

⑺Two-seat double rotary type, DCG. series, the maximum product carrying capacity is 500 tons

⑻Single rotary HTS series, HTS5, 9, 12, 20, 32, 40, 50, 60, 90, 160, 240, carrying capacity is 500. pounds to 240,000 pounds.

⑼Single-turn (rack and pinion) lifting type, HTS-GE series, HTS5 GE, HTS 240GE, with a load capacity of 500 pounds to 240,000 pounds.

2.3 German LCOOS Company

German LCOOS Company is one of the largest companies in the world that produces welding equipment. It also produces welding robots, welding machines and other products. In my country, in addition to the imported L-shaped double-rotation, tilt-rotation and single-rotation positioners that are matched with the welding robot system, we also produce horizontal single-seat single-rotation WPV and vertical single-rotation RR502. As well as positioners supporting various multi-axis welding robots, such as vertical multi-station 2×horizontal single-turn R-WPV type 2 (3 axes), vertical multi-station 2×C type double-turn R-WPV2 -CD (5 degrees of freedom), vertical multi-station 2×tilt-swivel GR-WPK 2 (5 axes), vertical multi-station 2×tilt-swivel×single-turn rotary GR-WPK 2- CD (9-axis), etc. The main parameters of these products, maximum allowable load capacity (max. admissible load capacity), are represented by N.

2.4 Panasonic Corporation of Japan

Japanese Panasonic is also a robot manufacturing company. This company produces 12 series of robot external equipment-welding positioners. They make the transmission device, machine base, clamping body, etc. into standard modules to form these product series. Classification of axis number and structural type. There are 3 series of 1-axis positioners, namely: vertical single rotation, horizontal single-seat single rotation, and double-seat single rotation; 2-axis positioners have 5 series, namely: C, L, H, quasi-L type double rotary type and 2×horizontal single seat single rotary type; 3-axis positioner has 3 series, namely: vertical multi-station, 2×vertical single rotary, horizontal multi-station 2×double-seat single-rotary type, 2×horizontal single-seat single-rotary type; there is 1 series of 5-axis positioners, vertical multi-station 2×L type double-rotary type.

Maximum payload (Max. payload) 200kg, 500kg, 1000kg.

2.5 Product introduction of domestic positioners

Nowadays, there are many manufacturers of welding positioners in my country, most of which are not large-scale. Enterprises developed with positioners as the leading products have not yet been formed. Positioners produced by Tianjin Dingsheng Company Engineering Machinery Co., Ltd., Wuxi Yangtong Machinery Equipment Co., Ltd., Changsha Haipu Company, Weida Automation Welding Equipment Company and other units occupy a large market in China. By 2000, more than 70 varieties and specifications of positioner products had been developed in China. The basic types of these positioners are briefly described below.

⑴ Full double rotary type. Including L, H (double seat), C type double rotary type (BZ2-, BZ2A-, BZ2B-, BZ2D- series).

⑵Tilt-rotary welding positioner (BZ2C-series).

⑶Single rotation welding displacement. Including three types: two-seat single-rotation type (BZ-, BZ1--, BZA--, BZA1-- series), two-seat single-rotation tailstock mobile type (BZY--, BZAY-, BZA1Y- series), single-seat Single rotation seat (vertical BZAL-, BZL-, horizontal BZW-, BZAW-inclined BZAX-series).

The above basic products have been developed into 17 series, mainly ordinary types, used for handle welding. In addition, there are speed-adjustable, joint control (PLC, microcomputer control) and robot matching products.

More than ten varieties of positioners have been developed for use with welding robots. Including: station change positioners (not involved in welding), such as vertical double-station, four-station, eight-station positioners, two-seater single-rotation eight-station and tilt-rotation double-station positioners. position machine, etc.; matched with the robot welding positioner (robot external axis), such as tilt-rotation servo transmission type, two-seat single rotation servo transmission type, multi-axis single rotation servo transmission type, etc.

3 Discussion on several basic definitions of welding positioner

3.1 Definition of welding positioner

In our country, welding positioner is A young product. Due to differences in development levels among manufacturing industries, many companies' welding stations are not equipped with welding positioners; at the same time, related research is relatively weak. So far, there are no special works to study its definition and classification. It is impossible to standardize its name. Different companies and different people may have different names for the same device. Such as: tire rotation, turntable, flip frame, positioner, positioner, etc. To do this, we need to give it a definition. We call it: the equipment used to drag the workpiece to be welded so that the weld seam to be welded moves to the ideal position for welding operations, is called a welding positioner. In other words, the workpiece is clamped on a piece of equipment and the welding operation is performed. The initial position of the welding seam to be welded may be in any direction in space. After the rotational displacement movement, the weld to be welded in any direction can be turned into ship fillet welding, flat welding or flat fillet welding operation. The equipment that completes this function is called a welding positioner. It changes the welding operations that may require vertical welding, overhead welding, etc. that are difficult to ensure welding quality. Thus, the welding quality is ensured, the welding productivity and the safety of the production process are improved.

3.2 Main degree of freedom and full-function welding positioner

It can be said with certainty that if a positioner drags the weldment, it only performs linear motion, even if it is It is three-dimensional and it is impossible to change the posture of the weld to meet the welding requirements. In other words, the displacement motion is a rotary motion, and this rotary motion is called the main degree of freedom of the positioner. We can also make this assumption: in the X, Y, Z rectangular coordinate system, there is a linear weld in space, which can rotate within 360° around the Z axis, and this Z axis together with this weld can also rotate around X ( Or the Y) axis rotates within the range of ≥180°, then the weld seam after this displacement can be changed to the ship's fillet welding position for welding operations. In other words, a welding joint consists of the center line MN and the angle α of two surfaces. Within the above two rotation ranges, with appropriate rotation, the center line MN can be parallel to the horizontal plane, and these two The angles between each plane and the horizontal plane are equal, each is α/2, which becomes the ship fillet welding position. This assumption is that any complex weldment can achieve ship welding requirements as long as it is installed on a welding positioner with a main degree of freedom of one full rotation and one half rotation. We call this double-rotation welding positioner a full-function positioner.

3.3 The degree of freedom of displacement of the welding positioner

Involves the user’s concept of equipment and equipment, as well as the different uses for hand welding and automatic welding, and the choice When designing a welding positioner, in addition to the main displacement freedom, it is also necessary to consider increasing the auxiliary displacement freedom. For example, welding of large parts can increase the freedom of lifting movement. There are many such products in the United States and Germany as mentioned above.

In addition, for some weldments, due to the simple distribution of welds, one degree of rotational freedom can solve the ship welding requirements for most of the important welds in the weldment, and the remaining small number of non-important welds, although , ship fillet welding cannot be performed, but flat fillet welding can be performed. In this way, in order to simplify the equipment cost, the welding positioner with a single degree of freedom or a degraded function is considered in the process, that is, a single-rotation positioner. Depending on the usage requirements, auxiliary degrees of freedom can also be added. For example, lifting type and moving tailstock type, etc.

There are also some station positioners that are suitable for the process requirements of the welding station. Some degrees of freedom of this welding positioner have nothing to do with welding. In addition, from the perspective of workstation design and stability, two or more welding positioners are designed to be combined, resulting in a variety of workstation transformation and combined multi-degree-of-freedom welding positioner products.

3.4 The first main parameter of the positioner - rated load

This article calls the parameter that best describes the working ability of the welding positioner the first main parameter. The welding positioner is different from other processing equipment in that its basic load is the "weight" of the weldment. The first main parameters of welding positioners in various countries are determined by this.

Internationally, the dimensions of the first principal parameter are not unified. This issue requires some discussion. In Europe, such as German Severt Company, CLOOS Company, Swedish ESAB Company, etc., it is expressed by the gravity unit N; the American Aroson Company is expressed by the British and American mass unit Lbs (pounds); some Japanese companies are expressed by the international mass unit kg; my country's welding The positioner industry standard uses the international mass unit kg, but Dingsheng Company uses the gravity unit kN. It can be seen that in our country and even internationally, the dimensions of the first main parameter of the welding positioner have not been unified. Secondly, the name of this main parameter is not uniform. Maximum load kg, maximum load N (Max load N), basic load capacity Lbs (Base load capacity in pounds), load capacity Lbs (Weight capacity Lbs), allowable load kg (allowable load), maximum effective load (Max. payload) and so on.

From the historical analysis of the development of dimensions, the two units of force and mass have their own reasons. However, whether it is considered from the perspective of industry management or scientific calculation, it should be unified. The author believes that the determination of dimensions lies in a concept. If the capacity of a welding positioner is measured and the load unit is selected, that is, the first principal parameter is expressed by gravity, then its dimensions should be expressed in N and kN. The related rotation technical parameters torque should be expressed in Nm and kNm, so that they are unified with the international system of units. This is the method recommended in this article.

Welding positioner is a product involving personal safety. It should be clear for users to select product load levels. For example, the above-mentioned maximum load (kg, N) or load (kg, N) cannot be said to accurately express this quantity. Now give a formula: F == kd m g n

In the formula: m is the mass of the weldment; g is the gravity acceleration, that is, mg is the gravity; kd is the dynamic load coefficient; n is the safety factor. Call F the rated carrying capacity or rated load. The dynamic load coefficient kd and safety factor n should be determined during product design. Provide users with selection methods in the catalog or instruction manual.

This article will not discuss the parameter series of rated load F and the two parameters of rotation or overturning moment.

4 Welding positioner type and function design

4.1 Type design

4.1.1 Degree of freedom design

⑴ There are three basic types of positioners designed with the main degree of freedom. ① Single rotation type, its rotation angle is ±360?·n; ② Double rotation type, its rotation angle is ±360?·n, the other is ±180?~±360? One of its turning angles is ±360?·n, and the other is ±(0?~(90, 135?)).

⑵ Multi-degree-of-freedom product design, adding auxiliary degrees of freedom to the above-mentioned basic products.

⑶Multi-degree-of-freedom combination structure design, which is designed by combining two or two basic products.

4.2 Structural design

⑴ Single-rotation type. In order to adapt to different workpiece clamping needs, there are three basic types, vertical, horizontal and double-seat. The two-seater is also divided into two types: fixed tailstock and movable tailstock. There are also head and tail splits, conjoined styles, etc.

⑵ Double rotary type. In order to adapt to the needs of different workpiece clamping and consider the reasonable structural stress, three basic types are also designed, L type, C type, H type (double seat double rotary type).

⑶ The tilt-rotation type also has different structural designs. For example, the rotation angle of one rotation is ±360? n, and the other is: ① ±45?; ② ± (0? ~ 90?); ③ ± (0? ~ 135?), etc., these three types have different structural types.

4.3 Functional design

⑴ Ordinary type, the rotary motion is fixed speed transmission.

⑵Speed-regulated type, at least one rotary motion is designed as a variable speed transmission.

⑶ Joint control type, in addition to the speed regulation function, uses PLC and microcomputer control to enable multiple machines and multiple degrees of freedom to work in conjunction.

⑷Robot-matching type, used as an external axis of the robot or involved in welding; or only for station change and not involved in welding.

5 Classification and model compilation method of welding positioner

5.1 Classification method

Considering the development of the small positioner industry, there must be a classification way. Every product that comes out can be given a legal code name. This is crucial for a positioner manufacturer, whether it is software or hardware management.

The so-called classification method is to arrange the products into a type spectrum based on the above-mentioned type design and the three characteristics of the product: degree of freedom, structure and function. In order to give them a code name to distinguish them from each other, this is the classification method.

5.2 Basic requirements for model compilation

Both classification and model compilation are for the same event. The classification method is to place a welding positioner on the type spectrum and give it a name. The model compilation method is to represent the named welding positioner with a set of character strings with certain characteristics. This string represents the product's degree of freedom, structural and functional characteristics, product parameter characteristics, replacement characteristics, etc.

5.3 Product code design

The code of the welding positioner is represented by a string, as shown in Figure 1. The first paragraph is the product code of the welding positioner, which can be represented by the Chinese Pinyin prefix HB or B; the second paragraph is the freedom classification code of the welding positioner, which is represented by the Chinese Pinyin prefixes Z and Y, which represent rotation and displacement freedom respectively. Degrees, 1, 2, 3... represent the number of degrees of freedom, single degrees of freedom can be left out by default; the third paragraph is the structural feature code of the welding positioner, mixed with the Chinese pinyin prefixes W, L, Q and shapes L, C, H means; the fourth paragraph is the function code of the welding positioner, using the Chinese pinyin prefixes T, S, K, and R to represent the speed regulating type, servo transmission type, joint control type and robot supporting type respectively, the ordinary type is default; the fifth paragraph The first section is the first main parameter of the welding positioner - the rated load code, expressed in Arabic numerals, in kN; the sixth section is the product replacement code of the welding positioner, in the order of development, using English letters A, B, C... Indicates that the first generation product defaults.

× ×

∣ ∣ ∣ ∣ ∟ Rated load code, expressed in Arabic numerals, unit kN

∣ ∣ ∣ ∟ Functional characteristic code, with Chinese pinyin prefixes T, S, K, R Representation, ordinary type defaults

∣ ∣ ∟ Structural feature code, represented by a mixture of Chinese Pinyin prefixes W, L, Q and shapes L, C, H

∣ ∟ Degree of freedom The code is represented by the prefixes Z and Y in Chinese Pinyin to represent rotation and displacement respectively, and the Arabic numerals represent the degrees of freedom

∟ The code of the welding positioner is represented by the prefix HB or B in Chinese Pinyin

Figure 1 Product code description of welding positioner

5.4 Basic series and group division of welding positioner

The basic series and group division of welding positioner, as shown in the figure 2 shown.

┌ L-type double rotary type (fixed, lifting type)

┌ Double rotary type│ H-type double-seater double rotary type (fixed, lifting type)

│ └ C-type double rotary type (fixed, lifting type)

│ ┌Single seat—┌Vertical BZL-

Welding positioner—│ Single rotary type —│ └Horizontal (fixed, lifting)

│ └ Two-seater--┌Tailstock fixed (fixed, lifting)

│ └Moving tailstock (fixed type, lifting type)

│ ┌- 0～135? (fixed type, lifting type)

└ Tilt-rotary type--│- 0～90? (fixed type, lifting type) Lift type)

└ -45?～＋45?

Figure 2 Classification of basic types of welding positioners

6 Conclusion

⑴ From the perspective of industry management, any product industry should have complete classification into categories. In the field of welding, if welding process equipment and welding machines are listed as one major category of products, then welding positioners can be used as a subcategory of welding process equipment. Compared with the main machine - "welding machine", the auxiliary machine - "positioner" is larger, heavier and more expensive than the main machine. It is more accurate to classify it as a subcategory of welding process equipment.

⑵ A small company in Germany produces more than 100 series of welding positioners. The type and functional designs given in this article also have dozens of product series, and have been developed in my country's construction machinery industry. What is incompatible with it is our country's standards. The "Welding Positioner" industry standard implemented in 1991, the so-called welding positioner, only has one series of tilting and rotating types. There was no fundamental change in the revision of the standard in 2000. The author hopes to use this as a basis to inspire others and form new standards.

⑶Involving the basic concepts of welding positioner, the definition, dimensions, etc. are explained in this article. In addition to other technical parameters, we do not seek international consistency, but seek domestic consistency. This enables enterprises to develop and compete under the same technical standards.

⑷ Regarding the method of compiling welding positioner model numbers, due to competition between companies, many companies are indifferent to the legal code names of their products. Adding the company name code to the product code name strengthens trademark awareness. Nonetheless, this article believes that at least the first principal parameter and dimension should be unified.

⑸The construction machinery industry has taken the lead in the development and application of welding positioners in my country in the past ten years. First of all, it is applied by large enterprises and foreign-funded enterprises. Foreign-funded enterprises have achieved non-ground welding. At present, in the technological transformation of joint-stock enterprises, they are gradually aligning with foreign-funded enterprises. Looking to the future, my country's welding displacement opportunities will develop healthily.

*Zheng Yongqiang, Secretary General of the Engineering Machinery Professional Committee of the Welding Association, Deputy Chief Engineer of Tianjin Engineering Machinery Research Institute

Reference: /chinese/jinianandahui/0312709.htm

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1. Welding classification:

Melt welding: During the welding process, both the base metal and the filler metal are melted, and the two are chemically combined. Such as: manual, CO2, TIG, MIG, submerged arc, MAG, plasma, laser, electron beam.

Pressure welding: No solder is used during welding, and the connected metals are chemically or physically bonded. The welding seam is narrow and the affected area is small. Resistance (point, seam) flash, friction, cold pressing.

Brazing: The temperature of the solder is lower than the temperature of the base metal. During welding, the solder melts but the base metal does not melt. There is a physical combination between the two. It is customary to use 450 degrees as the boundary between brazing and soft soldering. (Soft, hard) soldering iron, induction, furnace (vacuum) flame, resistance impregnation, arc, ultrasonic, laser, infrared

2. Brazing characteristics: (the longest history, the base material does not melt, The temperature is low, the deformation is small, and dissimilar materials can be combined and can be disassembled)

Brazing is a solid-phase connection. It is different from the melting welding method. The base metal does not melt during brazing, and the base metal is melted. For low-temperature solder, a connection method is adopted where the heating temperature is lower than the solidus line of the base metal and higher than the liquidus line of the solder. When the connected parts and the solder are heated until the solder melts, the liquid solder is used to wet the surface of the base material, spread and dissolve and diffuse with the base material, and wet, capillaryly flow, and fill the gaps between the base material and the base material. Dissolve and diffuse each other to realize the connection between parts.

Compared with fusion welding and pressure welding methods, brazing has the following advantages:

2.1 The brazing heating temperature is lower and has less impact on the structure and properties of the base metal; < /p>

2.2 The brazed joint is smooth and smooth, with beautiful appearance;

2.3 The deformation of the weldment is small, especially if the brazing method uses uniform heating (such as brazing in the furnace), the Deformation can be reduced to a minimum, and the dimensional accuracy of the weldment can be easily ensured;

2.4 Some brazing methods can weld dozens or hundreds of seams at a time, with high productivity:

2.5 It can realize the connection of dissimilar metals or alloys, metals and non-metals.

However, brazing also has its own shortcomings. The strength of the brazed joint is relatively low, and the heat resistance is relatively poor. Due to the large difference in the composition of the base metal and the brazing filler metal, the electrochemical corrosion caused by the corrosion resistance is reduced. Poor quality and relatively high assembly requirements.

3. Materials to be welded:

Metals: Cu, Fe, Al, Ti, Mg and other alloys

Cermet

Non- Metal (diamond, carbon fiber)

4. Brazing material and flux:

4.1 Brazing material

Cu-Zn, CuP, Ag, Al, Cd, Sn, Ni.

Application range of brazing filler metal

Hard

Brothering metal

The most widely used Cu-Zn based brazing filler metal is H62 can be used to braze plastic copper, nickel, and steel parts that are subject to high stress and require plastic joints. In order to prevent the volatilization of Zn, a small amount of Si can be added to H62; adding a small amount of tin can improve the spreadability of the solder.

CuP solder is a widely used air self-flux solder. Commonly used for brazing copper and copper alloys. When Wp=8.38%, Cut P forms a 7140C crystal. Cu3P is brittle, so the processability of CuP solder is not good.

Ag-based solder material Silver-based solder material can wet many metals and has good strength, plasticity and other comprehensive properties. It is widely used in brazing low carbon steel, structural steel, stainless steel, high temperature alloys, copper and copper alloys, etc.

Al-based solder is mainly used for brazing aluminum and aluminum alloys. Aluminum-based solder is mainly based on crystals of aluminum and other metals, and the commonly used ones are HL400 and HL401.

Ni-based solder is used for brazing parts that work at high temperatures. Nickel-based solder uses nickel as the matrix, and adds B, SI, P and other metal elements that can lower its melting point.

Soft

Brazing

Material Cd-based solder is mainly used for brazing copper and copper alloys. The working temperature can reach 2500C, and the brazing seam can be electroplated. Commonly used ones are HL506 and HL503.

Sn-based solder The most widely used solder is tin-lead solder. When WSn=61.9%, a gold crystal with a melting point of 1830C is formed. The working temperature of tin-lead solder does not exceed 1000C and is cold brittle at low temperatures.

Pb-based solder is generally used for brazing copper and copper alloys and can be used at operating temperatures below 1500C. Brazed joints have poor corrosion resistance in humid environments.

4.2 Flux

Fluoride, chloride,

The functions of flux: film removal, flow aid, protection

5 .Soldering methods:

Commonly used soldering methods, advantages and disadvantages

The soldering iron is easy to operate and is widely used in the electronics industry. It is only suitable for soft solder and soldering of thin and small parts

The flame is highly versatile and the process is relatively simple. It can be used for brazing aluminum alloys with aluminum-based brazing materials or brazing carbon steel and copper alloy small weldments with Cu and Ag-based brazing materials. The heating temperature is difficult to control and local heating produces stress

Resistance heating is rapid and easy to automate; the heating is concentrated and has little impact on the surrounding base metal. The shape and size of the brazed joint are strictly required, so the application is limited

p>

Induction heating has high efficiency and is widely used in weldments with symmetrical shapes such as steel and high-temperature alloys. It is difficult to accurately control the brazing temperature, and it is difficult to heat uniformly for weldments with uneven or asymmetric wall thickness.

Dip heating is rapid and even, and the brazing temperature is easy to control. It has high efficiency and can be divided into salt bath brazing and dip brazing of molten solder. The cost of production is high and it is not suitable for brazing weldments with deep holes, blind holes and closed weldments.

Furnace welding is heated evenly and the weldment is not easily deformed. High production efficiency. The brazing parts in the air furnace are seriously oxidized, the brazing cost in the vacuum furnace is high, and elements with high vapor pressure such as P\Cd\Na\Zn\Mg\Li cannot be used.

Diffusion improves the crystallization process of the brazing seam, obtains a balanced brazing seam structure, and improves the strength, plasticity, corrosion resistance, etc. of the brazing seam. Mostly used to connect active metal and refractory metal parts. The production cycle is long and the cost is high.

6. Induction welding:

Electromagnetic induction phenomenon, magnetic conversion, electrothermal conversion, magnetization, skin tendency, sharp angle, frequency, current coupling amount, voltage, material permeability, Number of turns

7. Pre-weld and post-weld treatment

7.1. Pre-weld treatment:

Part surface degreasing: organic solvent cleaning, alkali cleaning, electrochemistry Degreasing, ultrasonic cleaning

Removing surface oxides: mechanical cleaning, pickling

Pre-plating: process coating, barrier coating, solder coating

7.2. Post-weld treatment:

Post-brazing heat treatment: Improve the joint structure, perform diffusion heat treatment, eliminate brazing thermal stress, low-temperature annealing heat treatment

Remove flux:

Brother Methods for cleaning the types of flux used in welding

Organic flux, gasoline, alcohol, etc.

ZnCl2 NH4Cl 10%NaOH cleaning, then rinse with hot and cold water

Mechanical scratching with borax and boric acid flux or long-term soaking in boiling water

Mechanical scratching with calcium fluoride or long-term soaking in boiling water

Aluminum is hardened with chloride The flux is first carefully washed in water at 50-600C, and then surface passivated in a 2% chromic anhydride solution at 60-800C.

8. Brazability of materials and recommendations for commonly used brazing methods

The brazeability of materials refers to the difficulty of obtaining high-quality joints under certain brazing conditions. degree. For a certain material, if the brazing process is simpler and the quality of the brazing joint is better, the brazing performance of the material is better; conversely, if a complex brazing process is used, it is difficult to obtain high-quality joints. Then the brazing properties of this material are poor.

The primary factor that affects the brazeability of materials is the properties of the material itself.

For example, the surface oxides of Cu and Fe are low in stability and easy to remove, so Cu and Fe have good brazing properties; the surface oxides of Al are very dense and stable and difficult to remove, so aluminum has poor brazing properties.

The brazeability of materials can be examined from process factors (including which brazing material, flux and brazing method are used). For example, most solders have good wetting effects on Cu and Fe, but poor wetting effects on W and Mo. Therefore, Cu and Fe have good solderability, while W and Mo have poor solderability; another example is Ti And its alloys will form brittle compounds in the interface area after interacting with most brazing materials, so Ti has poor brazing properties; another example is that low carbon steel has lower requirements for a protective atmosphere when brazing in a furnace, and those containing AI and Ti High-temperature alloys can only obtain good joints when vacuum brazed, so low-carbon steel has good brazing properties, while high-temperature alloys have poor brazing properties. All in all, the brazability of a material is not only determined by the material itself, but also related to the brazing material, flux and brazing method. Therefore, a comprehensive evaluation must be carried out according to the specific situation.

Welding method

Material brazing

Soft soldering

Flame

In brazing furnace< /p>

Brazing?

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