Test Q & P(quenching and partitioning)steel(%:0. 17C

1.40Si

1.48Mn

0.25Al)was melted a 7.5 kg vacuum induction furnace then rolled to 1.0~1.5 mm plate.The heat treatment process of the test Q & P steel plate was simulated by a shaft salt bath furnace with austenizing at 910 ℃

quenching to 200~245 ℃ for 20 s

heating to parti-tioning temperature 300～450℃ for 60～600 s

then quick cooling.Results show that with quenching to 245℃ for 20 s

partitioning at 300～350℃ for ≥300 s

it is available to assure the carbon atom accumulating to residual austenite from martensite and get high product of strength-elongation(25000～30000 MPa%).