Type 302 screws and self-tapping bolts for mechanical processing.

The 303 type is improved for cutting performance by adding a small amount of sulfur to the 303 type stainless steel, which is used for processing nuts with rod material.

Model 304 is suitable for processing stainless steel screws using hot forging technology, such as longer specifications of bolts and larger diameter bolts, which may exceed the scope of cold forging technology.

The 305 model is suitable for processing stainless steel screws using cold heading technology, such as cold formed nuts and hexagonal bolts.

Type 309 and Type 310, both have higher Cr and Ni contents than the 18-8 stainless steel, and are suitable for stainless steel screws that operate at high temperatures.

Type 316 and 317, both contain the alloy element Mo, which makes them have higher high-temperature strength and corrosion resistance compared to 18-8 stainless steel.

Type 321 and Type 347, Type 321 contains more stable alloying element Ti, while Type 347 contains Nb, which enhances the material's resistance to intergranular corrosion. Suitable for stainless steel standard components that are not quenched after welding or serve at temperatures between 420 to 1013°C.

The material classification of stainless steel screws includes austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, and precipitation hardening stainless steel. The selection of stainless steel screws is also principled from what aspect to start, let you choose their own stainless steel screws.Through the five aspects of a comprehensive comprehensive consideration finally determine the selection of stainless steel screw brand variety specifications material standards

Austenitic stainless steel: the most basic alloying elements of austenitic stainless steel are chromium and nickel. The representative brand is chrome-nickel austenitic stainless steel containing about 18% chromium and about 8% nickel, often called 18-8 stainless steel. The ratio of chromium to nickel basically ensures that the structure of steel is stable austenite.

Iron type stainless steel: 430 ordinary chromium steel, its corrosion resistance and heat resistance is better than 410, magnetic, but it can not be heat treatment strengthening, suitable for corrosion resistance and heat resistance slightly higher, strength requirements of general stainless steel stainless steel screws.

Martensitic stainless steel: 410 and 416 can be heat treated to strengthen, with hardness ranging from 35 to 45 HRC, good machining performance, suitable for general use in heat and corrosion resistant stainless steel screws.

Type 416 has a slightly higher sulfur content and is a free-cutting stainless steel. Type 420, sulfur content? R0.15%, improved mechanical properties, heat treatment can be strengthened, the maximum hardness of 53~58HRC, used for higher strength stainless steel screws.

Precipitation-hardened stainless steel: 17-4PH, PH15-7Mo, they can get higher strength than the usual type 18-8 stainless steel, and are therefore used for high strength, corrosion-resistant stainless steel screws.

A-286, a non-standard stainless steel, has higher corrosion resistance than the commonly used 18-8 stainless steel, as well as excellent mechanical properties at higher temperatures. Used for high strength, heat resistant, corrosion resistant stainless steel screws, can be used to 650~700℃.

Austenitic stainless steel is commonly used in models such as 302, 303, 304, and 305. These four models are known as the 188 type austenitic stainless steel. These four models have similar corrosion resistance and mechanical properties. The production process of stainless steel screws starts with the method depending on the size and shape of the stainless steel screws.but also depends on the number of production

Type 302 for machined screws and tapping bolts.

In order to improve the machining performance, a small amount of sulfur is added to the 303 stainless steel, which is used for machining nuts with bar materials.

Type 304 is suitable for stainless steel screws processed by hot heading process, such as longer specification bolts, large diameter bolts, which may be beyond the scope of cold heading process.

Type 305 is suitable for the cold heading process of stainless steel screws, such as cold forming nuts, hex bolts.

Models 309 and 310, which have higher Cr and Ni content than type 18-8 stainless steel, are suitable for stainless steel screws working at high temperature.

Type 316 and 317, which contain the alloying element molybdenum, thus their high temperature strength and corrosion resistance are higher than type 18-8 stainless steel.

Type 321 and Type 347, type 321 contains relatively stable alloy element Ti, type 347 contains Nb, thus improving the resistance to intergranular corrosion. It is suitable for stainless steel standard parts which are not annealed after welding or service at 420~1013℃.