METHOD FOR MANUFACTURING AUSTENITE-FERRITE STAINLESS STEEL WITH IMPROVED MACHINABILITY

摘要

A method for manufacturing a plate, a band, or a coil of hot-rolled steel is provided. The method includes providing an ingot or a slab of steel with a desired composition and a microstructure composed of austenite and 35 to 65% ferrite by volume and hot rolling the ingot or slab at a temperature between 1150 and 1280° C. to obtain a plate, a band or a coil. A method for manufacturing a hot-rolled bar or wire of steel, a steel profile and a forged steel piece are also provided.

主权项

1. A method for manufacturing a plate, a band, or a coil of hot-rolled steel comprising the steps of:
providing an ingot or a slab of steel with a composition comprising in % by weight:
0.01%≦C≦0.10%20.0%≦Cr≦24.0%1.0%≦Ni≦3.0%0.12%≦N≦0.20%0.5%≦Mn≦2.0%1.6%≦Cu≦3.0%0.05%≦Mo≦1.0%W≦0.15%0.05%≦Mo+W/2≦1.0%0.2%≦Si≦1.5%Al≦0.05%V≦0.5%Nb≦0.5%Ti≦0.5%B≦0.003%Co≦0.5%REM≦0.1%Ca≦0.03%Mg≦0.1%Se≦0.005%O≦0.01%S≦0.030%P≦0.040%  the rest being iron and impurities resulting from the production and a microstructure being composed of austenite and 35 to 65% ferrite by volume, the composition furthermore obeying the following relations:
40≦IF≦65  with IF=10% Cr+5.1% Mo+1.4% Mn+24.3% Si+35% Nb+71.5% Ti−595.4% C−245.1% N−9.3% Ni−3.3% Cu−99.8; and
IRCGCU≧32.0  with IRCGCU=% Cr+3.3% Mo+2% Cu+16% N+2.6% Ni−0.7% Mn; and
0≦IU≦6.0  with IU=3% Ni+% Cu+% Mn−100% C−25% N−2(% Cr+% Si)−6% Mo+45; and hot rolling the ingot or slab at a temperature between 1150 and 1280° C. to obtain a plate, a band or a coil.