Impact stage low carbon steel hot-rolled sheet and mfg. method thereof

Abstract

A hot-rolled low-carbon steel sheet for punching contains proportionally C, Mn, S, P, Si, Al, Fe, Cr, B, Ti and Nb. Its preparing process includes such steps as heating to 1100-1150 deg.C, primary rolling, water cooling, fine rolling, winding, recrystallizing at 600-700 deg.C and annealing. Its advantages are high deep punching performance, plasticity, tension strength, and elongation percentage, and low yield strength.

Description

technical field

[0001] The invention relates to a metal material with good deep drawing performance and its manufacturing technology, especially to a metal material with good deep drawing performance, low yield strength, low yield ratio, good plasticity, high plastic strain ratio and hot rolling production Thin gauge mild steel sheet and method of manufacture thereof. Background technique

[0002] In recent years, ultra-thin (thickness less than 1.2mm) steel plates have been widely used in construction, automobile and beverage industries, but it is difficult to roll ultra-thin steel plates in the austenitic temperature range by conventional hot rolling processes. The traditional process is hot rolling in the austenite zone and then cold rolling with a large deformation of 70-80%, and then bell or continuous recrystallization annealing. The final product of this process is cold-rolled sheet, which is complicated and costly. high. With the rapid development of rolling techno...

Examples

Embodiment 1

[0038] The implementation process is carried out on the continuous casting and rolling production line, and the alloy composition is: C: 0.04%; Mn: 0.30%; S: 0.005%; P: 0.01%; Si: 0.02%; Al: 0.03%; Cr: 0.8%; B: 0.004%. Firstly, the slab is cast on the continuous casting machine and heated to 1100°C in the roller hearth furnace; then two passes of rough rolling are carried out, the rough rolling inlet temperature is 980°C, the billet is cooled by laminar flow after exiting the rough rolling mill, and then five passes of finishing are carried out. Rolling, the inlet temperature of the finishing mill is 820°C, and the outlet temperature is 750°C; the final high-temperature coiling, the coiling temperature is 680°C. The final hot-rolled sheet thickness was 1.2 mm.

[0039] The mechanical properties of the obtained hot-rolled sheet are as follows: tensile strength 320MPa, yield strength 220MPa, elongation 32%, work hardening index n value 0.24, plastic strain ratio r value 1.2.

Embodiment 2

[0041] The implementation process is carried out on the continuous casting and rolling production line, and the alloy composition is: C: 0.03%; Mn: 0.28%; S: 0.005%; P: 0.01%; Si: 0.03%; Al: 0.04%; Cr: 1.3%. Firstly, the slab is cast on the continuous casting machine and heated to 1100°C in the roller hearth furnace; then two passes of rough rolling are carried out, the rough rolling inlet temperature is 980°C, the billet is cooled by laminar flow after exiting the rough rolling mill, and then five passes of finishing are carried out. Rolling, the inlet temperature of the finishing mill is 820°C, and the outlet temperature is 750°C; the final high-temperature coiling, the coiling temperature is 680°C. The final hot-rolled sheet thickness was 1.2 mm.

[0042] The mechanical properties of the obtained hot-rolled sheet are as follows: tensile strength 325MPa, yield strength 230MPa, elongation 33%, work hardening index n value 0.23, plastic strain ratio r value 1.1.

Embodiment 3

[0044] The implementation process is carried out on the continuous casting and rolling production line, and the alloy composition is: C: 0.04%; Mn: 0.28%; S: 0.005%; P: 0.01%; Si: 0.02%; Al: 0.04%; Cr: 0.5%; B: 0.003%; Ti: 0.02%. Firstly, the slab is cast on the continuous casting machine and heated to 1100°C in the roller hearth furnace; then two passes of rough rolling are carried out, the rough rolling inlet temperature is 980°C, the billet is cooled by laminar flow after exiting the rough rolling mill, and then five passes of finishing are carried out. Rolling, the inlet temperature of the finishing mill is 820°C, and the outlet temperature is 750°C; the final high-temperature coiling, the coiling temperature is 680°C. The final hot-rolled sheet thickness was 1.2 mm.

[0045] The mechanical properties of the obtained hot-rolled sheet are as follows: tensile strength 315MPa, yield strength 210MPa, elongation 35%, work hardening exponent n value 0.24, plastic strain ratio r...

technical field

[0001] The invention relates to a metal material with good deep drawing performance and its manufacturing technology, especially to a metal material with good deep drawing performance, low yield strength, low yield ratio, good plasticity, high plastic strain ratio and hot rolling production Thin gauge mild steel sheet and method of manufacture thereof. Background technique

[0002] In recent years, ultra-thin (thickness less than 1.2mm) steel plates have been widely used in construction, automobile and beverage industries, but it is difficult to roll ultra-thin steel plates in the austenitic temperature range by conventional hot rolling processes. The traditional process is hot rolling in the austenite zone and then cold rolling with a large deformation of 70-80%, and then bell or continuous recrystallization annealing. The final product of this process is cold-rolled sheet, which is complicated and costly. high. With the rapid development of rolling techno...

Examples

Embodiment 1

[0038] The implementation process is carried out on the continuous casting and rolling production line, and the alloy composition is: C: 0.04%; Mn: 0.30%; S: 0.005%; P: 0.01%; Si: 0.02%; Al: 0.03%; Cr: 0.8%; B: 0.004%. Firstly, the slab is cast on the continuous casting machine and heated to 1100°C in the roller hearth furnace; then two passes of rough rolling are carried out, the rough rolling inlet temperature is 980°C, the billet is cooled by laminar flow after exiting the rough rolling mill, and then five passes of finishing are carried out. Rolling, the inlet temperature of the finishing mill is 820°C, and the outlet temperature is 750°C; the final high-temperature coiling, the coiling temperature is 680°C. The final hot-rolled sheet thickness was 1.2 mm.

[0039] The mechanical properties of the obtained hot-rolled sheet are as follows: tensile strength 320MPa, yield strength 220MPa, elongation 32%, work hardening index n value 0.24, plastic strain ratio r value 1.2.

Embodiment 2

[0041] The implementation process is carried out on the continuous casting and rolling production line, and the alloy composition is: C: 0.03%; Mn: 0.28%; S: 0.005%; P: 0.01%; Si: 0.03%; Al: 0.04%; Cr: 1.3%. Firstly, the slab is cast on the continuous casting machine and heated to 1100°C in the roller hearth furnace; then two passes of rough rolling are carried out, the rough rolling inlet temperature is 980°C, the billet is cooled by laminar flow after exiting the rough rolling mill, and then five passes of finishing are carried out. Rolling, the inlet temperature of the finishing mill is 820°C, and the outlet temperature is 750°C; the final high-temperature coiling, the coiling temperature is 680°C. The final hot-rolled sheet thickness was 1.2 mm.

[0042] The mechanical properties of the obtained hot-rolled sheet are as follows: tensile strength 325MPa, yield strength 230MPa, elongation 33%, work hardening index n value 0.23, plastic strain ratio r value 1.1.

Embodiment 3

[0044] The implementation process is carried out on the continuous casting and rolling production line, and the alloy composition is: C: 0.04%; Mn: 0.28%; S: 0.005%; P: 0.01%; Si: 0.02%; Al: 0.04%; Cr: 0.5%; B: 0.003%; Ti: 0.02%. Firstly, the slab is cast on the continuous casting machine and heated to 1100°C in the roller hearth furnace; then two passes of rough rolling are carried out, the rough rolling inlet temperature is 980°C, the billet is cooled by laminar flow after exiting the rough rolling mill, and then five passes of finishing are carried out. Rolling, the inlet temperature of the finishing mill is 820°C, and the outlet temperature is 750°C; the final high-temperature coiling, the coiling temperature is 680°C. The final hot-rolled sheet thickness was 1.2 mm.

[0045] The mechanical properties of the obtained hot-rolled sheet are as follows: tensile strength 315MPa, yield strength 210MPa, elongation 35%, work hardening exponent n value 0.24, plastic strain ratio r...