We make many fasteners and screws used in most factories in the world, and there are many screws with good quality, depending on which one you use. Carbon steel below grade 8.8, 12.9 alloy steel, and screws coated with hot zinc are not easy to rust for many years. Stainless steel screws are rarely used in industry, and their strength is not enough. Most of them are used in some medical devices, food production lines, and some equipment that does not require large torque. Getting what you pay for depends on the cost of your purchase.

First, bolts, which are widely used and simple fasteners, are not high in technology and we can't do it. The key is the price.

Bolt is steel, and iron is a relatively active metal, which is easy to oxidize in the air, especially in a humid environment. In fact, we only need to do a metal surface treatment, but the metal itself will not rust without contact with oxygen, or the metal material used to make bolts will not rust if it is replaced with stable stainless steel! However, the manufacturing cost will increase. In general, we solve problems from low to high economic conditions. After all, there is not much money.

Secondly, we know that the main cause of bolt rust is oxidation.

The first is to isolate oxygen from metal contact, so that it will not rust. After the bolt is tightened, it will be stained with vaseline or butter, and then coated with metal antirust paint, which is the cheapest solution.

The second method is to coat the bolt with a stable metal layer. Usually bolts are cleaned, degreased and derusted first, then plated with copper and then galvanized. The disadvantage is that the process cost is much more expensive.

Thirdly, 304 stainless steel can be used stably for many years, and 3 16 stainless steel can also be better resistant to salt and alkali and corrosion. Al-Mg alloy can be used in some places with low strength. Titanium alloy bolts with higher strength can also be used in places with higher requirements for the use environment. Of course, the price is soaring.

I hope my answer can help you.