AUSTENITIC STAINLESS STEEL

Austenitic stainless steel is the most popular of all the stainless steel now produced. The basis component and content of this alloy follows: 17-26% Cr; 7-26% Ni; 2.0-4.5%Mo; 1.5-2.5%Cu; <=0.12%C and small quantities of alloying elements as: Ti, Nb etc.

Austenitic stainless steel is nonmagnetic, can not be harden by heat treatment and has good welding performance generally. It suits to cold working for its good ductility does not alter largely under calcinations. If carbon content of austenitic stainless steel is high relatively, it can become martensitic structure partly when cold finished, and slightly magnetic comes part.


AISI304/1.4301, AISI304L/1.4306, AISI321/1.4541

They belongs to Ni-Cr-Fe alloys and are used in industry
1.4301 Carbon content is not up to an extent of 0.07%, Cr content varies from 17 to 19%, nickel content varies from 8.5 to 10%. This alloy is better than Cr-Fe steel in corrosion resistance. The weld seal does not need post weld heat treatment when this alloys that thickness is not up to 6mm welds.

1.4306 is similar as 1.4301 approximately, Carbon content is not up to an extent of 0.03%. It has good accessibility to the welding process and no liquation carbide (the cause of intergranular corrosion)

1.4541(containing addition agent-Ti) It can exist a stable structure at analogous alloys under the critical temperature (between 450~800¡æ). 1.4306 and 1.4541 generally replace up to 6mm 1.4301 alloy, since it take more time under welding for 1.4301 than others and the risk of intergranular corrosion increases relatively. 1.4306 has better heat stability than 1.4541 alloy evidently, so it is suited for the circumstance that rather exists stress under high temperature. Both do not become flakes below 870¡æ. 1.4306 and 1.4541can apply both at low temperature also(<=270¡æ).


AISI316/1.4401-1.4436,AISI316L/1.4404-1.4435,AISI316Ti/1.4571


Corrosion resistance of Ni-Cr stainless steel can improve evidently by increasing molybdenum additions content. Trend of Ferrite congregation induced by molybdenum of austenitic structure can be controlled by altering nickel addition content. 1.4401, 1.4436, 1.4404, 1.4435 and 1.4571 alloys have good corrosion resistance for organic, inorganic acid and alkali that produce reductive corrosion, do not bring intergranular corrosion generally. 1.4435 and 1.4571 alloys are suited to the 270¡æ circumstance. The weld seal does not need post weld heat treatment when this alloys that thickness is not up to 6mm welds. Low carbon content alloy 1.4401, 1.4436 and alloy 1.4571with titanium addition all do not bring intergranular corrosion, so all the weld seal does not need post weld heat treatment, and are able to run continually below 800¡æ. All three alloys do not become flakes below 870¡æ. Alloy 1.4401, 1.4571 are most popular used corrosion resistance and acid resistance stainless steel material in chemical engineering. Alloy 1.4571 has better heat resistance for containing molybdenum addition than alloy 1.4435, and worse acid corrosion resistance yet.

AISI904L/1.4439

Alloy 1.4439 is a excellent acid corrosion resistance stainless steel now produced. It has excellent corrosion resistance for H2SO4 and H3PO4 at 70% and 80¡æ, and better corrosion resistance for concentrated organic acid, salt solution, carbonate water etc. . This type of alloy does not become intergranular corrosion and stress corrosion cracking, the weld seal does not need post weld heat treatment, for its carbon content <=0.03%. It is able to run continually at the 800¡æ also.