SUS304 

 SUS304 Heat treatment specifications: fast solution 1010 ~ 1150 ℃ cold. Microstructure: Organizing for the austenitic type. SUS304 or 18 / 8 stainless steel. GB grades for 0Cr18Ni9. Japan's JIS standard material SUS304, SUS series austenitic stainless steel in Japan. Equivalent to China's 0Cr18Ni9, 304 U.S. editorial features in this section 
 Has good corrosion resistance, heat resistance, low temperature strength and mechanical properties, hot stamping and bending process is good, no-hardening heat treatment, non-magnetic. 

 Heat treatment 
 Because it contains high nickel and at room temperature was austenite single phase structure, so it is with the stainless steel Cr13 
 SUS304 
 Steel compared with high corrosion resistance at low temperatures, room temperature and high temperature plastic go and have a higher toughness, and good cold forming and welding. However, a lower room temperature strength, intergranular corrosion and stress corrosion tend to be larger, poor machinability. Austenite no phase change when heated, it is not strengthened by heat treatment. Only to improve the corrosion resistance of steel heat treatment: 1) solution treatment; its purpose is to make carbon at room temperature to fully dissolve and remain in the austenite, which at room temperature by single-phase austenite, the Steel has the highest resistance to corrosion. Solution treatment temperature is generally higher the heating, between the 1050-1100C, according to the level of carbon content to make appropriate adjustments. As the poor thermal conductivity of 18-8 stainless steel, not only to warm up and then quenched by heating, but also in the solution heat treatment (quenching) when the holding time is longer. Solution treatment, we should pay special attention to prevent the growth of carbon. 18-8 will increase because of increased carbon steel intergranular corrosion tendencies. Cooling medium, generally water. After solution treatment organizations are generally single-phase austenite, but titanium, niobium, molybdenum stainless steel, especially when the castings, also contains a small amount of ferrite. Hardness after solution treatment is generally 135HBS so. 2) In addition to stress annealing; in order to eliminate the residual stress after cold working, processing at lower temperatures. Usually heated to 250-425C, is frequently used 300-350C. For the non-titanium or niobium steel should not exceed 450C, in order to avoid chromium carbide precipitation 
 SUS304 
 Caused by intergranular corrosion. In order to eliminate the residual stress after welding, eliminating the stress corrosion susceptibility of steel to the processing at higher temperatures. Heating temperature is not lower than 850C. Cooling, the steel containing titanium or niobium can be directly cooled in the air; that do not contain titanium or niobium steel should be cooled to 500C after cooling in the air again. 3) stabilization process; titanium and niobium in order to prevent the welding of austenitic stainless steel or solid solution treatment, due to a decrease in TiC and NbC cause reduced resistance to intergranular corrosion, this stainless steel will be heated to a certain temperature (the temperature to completely dissolve in austenitic chromium carbide, and only partial dissolution of TiC and NbC) and then slow cooling. In the cooling process, so full of carbon steel with titanium and niobium compounds, precipitation of stable TiC and NbC, without precipitation of chromium carbides, thereby eliminating the 18-8 austenitic stainless steel intergranular corrosion tendencies, such process is called stabilization treatment. 18-8 stainless steel stabilization annealing is generally heated to 850-880C, heat 2-6h, followed by air cooling or furnace cooling. 

 Chemical composition 
 Carbon C: ≤ 0.07 Si Si: ≤ 1.00 Chromium Cr :17.00-19 .00 Manganese Mn: ≤ 2.00 Ni Ni :8.00-11 .00 Phosphorus P: ≤ 0.035 S S: ≤ 0.030 Mechanical Properties Edit this paragraph 
 Yield strength (N/mm2) ≥ 205 Tensile strength ≥ 520 Elongation (%) ≥ 40 hardness HB ≤ 187 HRB ≤ 90 HV ≤ 200 density of 7.93 g · cm-3 specific heat c (20 ℃) ??0.502 J · (g · C) -1 Thermal conductivity λ / W (m · ℃) -1 (in the following temperature / ℃) 20 100 500 2.1 16.3 21.4 linear expansion coefficient α / (10-6 / ℃) (at room temperature following / ℃ ) 20 100 20 200 20 300 20 400 16.0 16.8 17.5 18.1 resistivity 0.73 Ω · mm2 · m-1 melting point of 1398 ~ 1420 ℃