Stainless steel grade “304″ (S30400) is the U.S. steel standards (such as ASTM standards) in the grade name. In newly developed stainless steel grade standards GB/T20878-2007, the corresponding grades are 06Crl9Nil0 (old grade forOCrl8Ni9). This grade is well-known 18-8 Cr-Ni austenitic stainless steel grades typical. Because of its excellent performance, wide range of uses, so its production and consumption accounts for austenitic stainless steel is about 80% of the total.

Advantages:

1. Stainless steel with excellent corrosion resistance and good resistance to intergranular corrosion. Of oxidizing acids, such as concentration ≤ 65% below the boiling temperature of nitric acid, with strong corrosion resistance. Most of the alkali solution and organic acids and inorganic acids also has good corrosion resistance.

2. Excellent hot and cold forming process and performance. Can processing board, tube, wire,tape, type of product, for the manufacture of cold heading, deep drawing, deep drawing forming parts.

3. Better low temperature performance. At -180 ℃ condition, strength, elongation, area reduction rate is very good. In the absence of brittle transition temperature, often used at low temperatures.

4. Has good weldability. Welding method can be used often, both before welding without heat treatment after welding.

Disadvantages:

1. Large section size steel intergranular corrosion after welding sensitive;

2. C1-containing water (including wet air) is very sensitive to stress corrosion;

3. Low mechanical strength, such as poor cutting performance.

Since 304 there lack of performance, people in the production and use to find ways to avoid weaknesses, optimize the development of its excellent performance, to overcome its shortcomings. Thus, through research and development, according to different environmental conditions or specific requirements, to adjust its chemical composition, developed to meet the requirements to use certain features derived from 304 grade.