Strip mill lines

Strip steel rolling mill line:

Strip steel products are generally categorized into hot-rolled strips and cold-rolled strips. Strips with width under 600mm are named as narrow strip, with width above 600mm named as wide strips.

Hot rolled strip is widely used in architecture finishing engineering, color coated sheets for doors and windows, cold-rolled billet, cold-forming billet, welded tube billet, manufacture of small metal products, and etc.

Process flowchart of hot-rolled strips:

Reheating furnace →Descaling machine → Roughing mill → Descaling machine → Finishing mill → surface inspection instrument → Laminar cooling → Coiling machine -→ Bundling machine → Spray marking machine → warehouse

Hot-rolled strips production process:

First, the slab is heated in reheating furnace to get the required rolling temperature, then conveyed by roller into rough rolling descaling machine for scale clean treatment, and then into the rough rolling mill to be rolled to certain width and thickness. The rolled strip then is transported by roller to the finishing mill for surface descaling, then into the finish rolling mill for more precise rolling. Next, the strips shall take laminar cooling in order to control the surface temperature before coiling. After coiling, bundling, and number marking are taken successively, the strips are transferred into warehouse.

Main technical data:

Production line	Continuous casting billet		Final products (mm)		Steel grade	TPA (ton)	Weight per coil（t）	Model of machine
	Section	Length
500 hot-rolled strip production line	150×150 165×280 165×320	4500	1.8~5	145~355(400)	Common carbon steel; Low-alloy steel	60	0.75~2	Core-free coiling and collecting
							1.2~215	Vertically coiling collection
550 hot-rolled strip production line	150×150 165×280 165×320 165×380	6000	2~6	250~400	Stainless steel ;Low-alloy steel	60	<2	Core-free coiling and collecting
							1.2~3.5	Vertically coiling collection
650 hot-rolled strip production line	165×320 165×380 180×480	4500	2~6	350~500	Common carbon steel; Low-alloy steel; Stainless steel	80	<3.5	Horizontal core coiling
							>3.5	Horizontal core coiling with four wrapping rolls
700 hot-rolled strip production line	165×380 180×480 180×550	6000	2~6	350~585(600)	Common carbon steel; Stainless steel; Low-alloy steel;	80	<5.5	Horizontal core coiling with four wrapping rolls
750 hot-rolled strip production line	165×380 180×480 180×550 180×580	6000	2~6	350~600	Common carbon steel; Stainless steel; Low-alloy steel;	80	<6	Horizontal core coiling with four wrapping rolls
800 hot-rolled strip production line	180×480 180×550 180×580 180×630	7000	2~6	450~650	Common carbon steel; Stainless steel; Low-alloy steel;	90	<6.5	Horizontal core coiling with four wrapping rolls
850 hot-rolled strip production line	180×480 180×550 180×580 180×630 180×680	7000	2~6	500~700(730)	Common carbon steel; Stainless steel; Low-alloy steel;	100	<7	Horizontal core coiling with three wrapping rolls
950 hot-rolled strip production line	180×480~780	7000~8000	2~6	550~800	Common carbon steel; Stainless steel; Low-alloy steel;	100	<8	Horizontal core coiling with three wrapping rolls

Cold-rolled strips are widely used in engineering machinery, transportation machinery, construction machinery, lifting appliance, agricultural machinery, and common steel members and press pieces for light and civil industry.

Process flowchart of cold-rolled strips:

Pickling line → rolling → quenching → lubricating → coating with rustproof oil →cutting to length →polishing → packing

Strengths of cold rolled strips:

1. Cold rolled strips could be very thin, reaching to 0.001mm. This is hard to be achieved by hot rolling.

2. The end products have advanced and widely used mechanical and process properties.

3. Cold rolled strips have highly accurate dimension, little deviation in thickness, good shape, and smooth surface.

4. Low cost while high output.

5. Fast speed of rolling with high productivity.

Process characteristics of cold-rolled strips:

1. When cold rolling is taken, the strips will be harden during processing. Thus, quenching is necessary to soften the strips so as to restore the flexibility for continuous rolling.
2. Clean the scale on the surfaces of strips before rolling in order to keep the surfaces smooth as well as to reduce abrasion of rollers.
3. Apply tension rolling to guarantee strips in good shape, to control the deviation in thickness, and to reduce rolling pressure for the benefit of thin strip rolling.
4. Apply process cooling and lubrication to easily control the temperature of rollers and strips, and to reduce the abrasion between rollers and strips, as well as reduce the rolling pressure, so as to properly control shape of strips and prevent them from roll banding. Cold-rolled strips and steel plates are generally 0.1~3mm thick and 100~2000mm wide, made of hot rolled strips or steel plates by means of cold rolling mill. They are of smooth and clean surface, accurate dimension, and good mechanical properties. Most of the cold-rolled strips and steel plates will be made into coils, or coated with oil painting as colored coated sheets. Coiled cold-rolled steel sheets have high productivity and are easy to use and be processed. The production of cold-rolled strips and steel sheets occupies 30% of total production of steel products in developed industrial countries. In addition to the common carbon steel, steel grades include silicon steel, stainless steel, alloy steel, and etc.