HMPT-BOF-RH-CSP process for SPHE substrate of cold rolled deep drawing steel

Based on hot metal pretreatment (HMPT)-basic oxygen furnace (BOF)-Rheinstahl Heraeus (RH)-compact strip production (CSP) process, parameters controlling on cold rolling deep drawing substrate SPHE were investigated during smelting and rolling process by composition design and technology control. The influence of parameters on chemical compositions, mechanical properties and microstructure was revealed by scanning electron microscope (SEM). The results show that, 1) main chemical components in SPHE are w(C)≤40×10−6, w(Si)≤ 0.01%, w(S)≤0.009%, w(N)≤20×10−6, w(O)≤ 25×10−6; 2) main mechanical properties of the SPHE are σs=274 MPa, σb=334 MPa, A=48.9%; 3) main performances of deep drawing quality (DDQ) grade steel produced by SPHE are as follows, transversely σs=167 MPa, σb=298 MPa, n=0.219, r=2.46; vertically σs=166 MPa, σb=298 MPa, n=0.226, r=2.39; in 45° direction σs=171 MPa, σb=308 MPa, n=0.214, r=2.26; 4) microstructure of DDQ is ferrite, average grain size is Grade 7.5, and inclusion size is 3–10 μm.