321 Ti stainless steel in which the elements exist as stable, but it is also hot strong steel at high temperatures much better than the .321 316L stainless steel in different concentrations and different temperatures of the organic acids and inorganic acids, especially in oxidizing medium has good corrosion-resistant properties, for the manufacture of wear-resistant acid containers and equipment lining, pipeline 321 stainless steel is Ni-Cr-Mo-type austenitic stainless steel, its performance is very similar with the 304, but due to join the titanium, it has a better resistance to grain boundary corrosion and high temperature strength. The addition of titanium to make it effective control of the chromium carbide formation. 321 stainless steel with excellent high-temperature stress rupture (Stress Rupture) performance and high-temperature creep resistance properties (Creep Resistance) stress mechanical properties are superior to 304 stainless steel. 
 Application 
 Applied to grain boundary corrosion resistance for high chemical, coal, oil industry, the open field machinery, building materials, heat-resistant parts and difficult parts heat treatment 1 oil combustion exhaust pipe (2) the engine exhaust pipe 3 boiler shell, heat exchanger , furnace parts 4 parts diesel engine with silencer 5 boiler and pressure vessel 6 chemical truck 7. expansion joints 8 burner pipes and dryer with spiral welded pipe 
 Tolerance 
 321 stainless steel size and tolerance level of standard deviation of diameter tolerance 
 D1 ± 1.5%, min ± 0.75 mm 
 D2 ± 1.0%. Minimum ± 0.50 mm 
 D3 ± 0.75%. Minimum ± 0.30 mm 
 D4 ± 0.50%. ± 0.10 mm minimum 
 Stainless steel weight formula: [(OD - Wall Thickness) * Thickness] * 0.02491 = kg / m (weight per meter) [1] edit the physical properties of this paragraph 
 Chemical composition 
 Carbon C: ≤ 0.08 Si Si: ≤ 1.00 Manganese Mn: ≤ 2.00 S S: ≤ 0.030 P P: ≤ 0.035 Cr-Cr: 17.00 ~ 19.00 Ni-Ni: 9.00 ~ 12.00 Titanium Ti: ≥ 5 × C% [2] Mechanical Properties 
 Tensile strength σb (MPa): ≥ 520 conditions yield strength σ0.2 (MPa): ≥ 205 Elongation δ5 (%): ≥ 40 Reduction of ψ (%): ≥ 50 Hardness: ≤ 187HB; ≤ 90HRB; ≤ 200HV [3] and microstructure heat treatment specifications 
 Heat treatment specifications: 1) solution 920 ~ 1150 ℃ rapid cooling; 2) According to the demand side, demand can be stabilized, heat treatment temperature of 850 ~ 930 ℃, but it must be stated in the contract