HPB235 (hot rolled polished rod), also known as Q235.

HRB335 (hot rolled ribbed bar), hot rolled ribbed bar, also called 20MnSi.

HRB400 (hot rolled ribbed bar), hot rolled ribbed bar.

RRB400 (waste heat treated ribbed steel bar), waste heat treated steel bar.

Grade HPB235: stable quality, good plasticity, easy to form, but low yield strength, not suitable for steel bars in structures;

HRB335: Ribbed reinforcement is beneficial to bond with concrete, and has good strength and plasticity, which is the main application at present.

One of the steel varieties used;

HRB400 grade: Ribbed steel bars are beneficial to bond with concrete, and have good strength and plasticity, so they should be the main varieties in the future.

One of the steel varieties used;

RRB400 grade: HRB335 steel bar is rapidly cooled after hot rolling, and tempered by the internal temperature of steel bar. The strength of quenched steel bars is improved, but the plasticity is reduced, and the plasticity is improved after waste heat treatment. Production conditions are limited, and the current output is limited.

Steel bars can be divided into hot rolling, cold drawing, cold rolling and heat treatment according to different processing methods.

H stands for hot rolling, P stands for aperture, B stands for reinforcement, R stands for ribbed, and the first R in RRB stands for waste heat treatment.

For the grade of hot rolled steel bars, the higher the strength of I-IV grade, the worse the plasticity. Grade I, namely HPB235, is mostly round, and grade II-IV.

They are HRB335, HRB400 and HRB540, all of which are straight.

Heat-treated steel bar is a kind of steel bar obtained by quenching and tempering of four-grade hot-rolled steel bar, and its strength ratio is four.

Grade I steel bars are much higher, but the plasticity is not much reduced, which is used for large prestressed concrete members.

As for the price of steel bars, it has been fluctuating with the market, and now steel bars are listed and traded in futures. The current secondary reinforcement is 3900.

Per ton, the first grade is more expensive than others 100 yuan, and the residual heat treatment steel bar is more expensive than the second grade steel bar 1000 yuan. Now that the construction market is gradually picking up, the price of steel bars should rise. Non-national special projects all adopt primary, secondary and partially prestressed cold-drawn steel bars. For most of us who are engaged in projects, RRB basically exists in books.

The cast-in-place reinforced concrete slab is designed as HPB235@ 150, and the reinforcement purchased on site is HRB335. How to calculate the replacement with equal strength? Thank you very much

A: N *2 10= M *3 10.

N is the number of design elements. M is the number of replacement roots.

At present, HRB400 steel bars are generally used for the bottom plate of raft foundation, and HRB335 and HPB235 steel bars are generally used for strip foundation. The principle of structural reinforcement is economical, applicable and reasonable.

What's the difference between steel frame structure and reinforced concrete structure? Which is better for earthquake resistance?

1) steel frame structure is mainly made of steel, which is one of the main types of building structures. It has the following characteristics: light weight, high working reliability, good vibration (impact) resistance and impact resistance, high degree of industrialization and easy to manufacture compactly.

Sealed structure, easy to corrode, poor fire resistance.

(2) Reinforced concrete structure is a structure composed of steel bars and concrete. Steel bars bear tension and concrete bears pressure.

Compared with steel structure, it has the advantages of durability, good fire resistance, steel saving and low cost.