Cold rolling: Using hot-rolled steel coils as raw materials, oxidizing the hides and removing the scales and then performing tandem cold rolling. The finished products are rolled hard rolls. The cold work hardening due to continuous cold deformation makes the strength, hardness, and toughness of the rolled hard rolls rise. The plastic index drops, so the stamping performance will deteriorate, and it can only be used for simple deformed parts. Rolled hard coils can be used as raw materials for hot dip galvanizing plants because hot dip galvanizing units are all provided with annealing lines. The weight of the rolled hard coil is generally 6~13.5 tons. The coil is continuously rolled at room temperature under the normal temperature. The inner diameter is 610mm.
Because it has not been annealed, its hardness is very high (HRB is greater than 90), and its machining performance is extremely poor. It can only perform simple directional bending processing (with a direction perpendicular to the take-up direction) of less than 90 degrees.
JIS G3141-SPCC-SD, SPCC-SB, SPCD-SD, SPEC-SD
JIS G3135-SPFC 340/390/440
EN10130-DC01, DC03, DC04
To put it simply, cold rolling is performed on the basis of hot-rolled coils. Generally speaking, it is hot-rolling, pickling, and cold-rolling.