Temper Rolling Mill: practical notes from the shop floor and the boardroom

If you work with cold-rolled strip, you know the finishing pass can make or break downstream performance. I’ve walked more lines than I can count, and, to be honest, the temper pass is where the magic happens—locking in flatness, toning down yield-point elongation, dialing surface roughness. A good Temper Rolling Mill is equal parts metallurgy and control engineering, with a dash of operator instinct.

What’s trending in temper mills (and why buyers care)

Three currents I keep hearing from plant managers: tighter flatness (≤ ≈8 I-units) for EV and appliance skins; deterministic Ra control (e.g., Ra ≈0.6–1.2 μm for paintability); and energy-smart soft reduction to gently tweak thickness while stabilizing mechanical properties. Surprisingly, many customers say real gains came from smarter AGC/AFC tuning rather than a hardware swap. Software eats steel, too.

Core functions (in plain English)

• Suppress yield-terrace and stabilize YPE—better deep draw behavior.
• Clean up the surface and set controlled roughness for coatings or lamination.
• Improve flatness/straightness for consistent coil geometry.
• Soft reduction to nudge thickness and fine-tune mechanical properties.

Typical technical specs

Parameter	Typical Range (≈)	Notes (real-world use may vary)
Strip width	600–1,850 mm	Dependent on stand and payoff/tension reels
Thickness	0.2–3.0 mm	Soft reduction up to ≈1–2%
Entry speed	200–1,200 m/min	High-speed lines need robust AFC
Roughness (Ra)	0.4–1.8 μm	Per ISO 4287/4288; shot/blasted roll textures
Flatness	≤ 8–12 I-units	Feedback from coil maps + laser shape meters

Process flow, materials, and testing

Materials: low-carbon CR, IF steels, tinplate base, some ferritic stainless; occasional Al coils (with adjusted rolls). Methods: entry inspection → cleaning/brush → lubrication → temper stand (2-/4-high) with AGC/AFC → electrostatic oiler or chem coater → exit inspection. Testing: tensile per ISO 6892-1/ASTM A370, surface per ISO 4287, deep draw per EN 10130, coating adhesion per ASTM D3359. Service life: work rolls ≈ 8,000–15,000 t per grind; bearings typically 3–5 years with proper lube.

Where it earns its keep

• Automotive skins and EV battery casings (flatness and paintability).
• Appliance panels—customers often report fewer orange-peel defects.
• Packaging steel (tinplate base)—tight gauge and smooth surfaces.
• Construction profiles and PPGI lines—consistent Ra improves coating gloss.

Vendor snapshot (informal comparison)

Vendor	Config	Automation	Lead Time	Certs
YWLX (Beijing)	2-/4-high, soft reduction	AGC/AFC, coil map, MES hooks	≈ 5–8 months	ISO 9001 (typ.)
SMS group	High-speed temper lines	Advanced model predictive	≈ 8–12 months	ISO/CE
Primetals/Danieli	Integrated finishing lines	Level 2/3 integration	≈ 9–14 months	ISO/CE

Customization checklist

• Roll texture library (electro-discharge, shot, hybrid) for target Ra/Rz.
• AGC/AFC tuning for thin gauges; add shape meter and bend/crown control.
• Coil logistics: quick-threading, automatic tail stitching, camera QC.
• Energy package: regenerative drives, smart lubrication.

Quick case note

An Asia-Pacific appliance producer upgraded to a Temper Rolling Mill with soft reduction and tighter AFC. Over 90 days, paint rejects dropped ≈32%, flatness improved to ≤10 I-units on 0.5–0.8 mm coils, and line speed rose by ~12%. Their maintenance chief told me, “Honestly, tuning beat hardware. Once the coil map was dialed in, the line behaved.”

Compliance, testing, and documentation

Look for ISO 9001 and CE marking; verify mill test certificates with tensile per ISO 6892-1/ASTM A370, surface per ISO 4287/4288, and DC grades per EN 10130. For traceability, ask for Level-2 data trails and coil genealogy.

Origin: No.1518, LAR Valley Int'l, Guang’anmen Avenue, Xicheng District, Beijing, 100055

Authoritative references

1. ISO 6892-1: Metallic materials — Tensile testing, Method A.
2. ASTM A370: Standard Test Methods and Definitions for Mechanical Testing of Steel Products.
3. ISO 4287/4288: Geometrical product specifications — Surface texture profile methods.
4. EN 10130: DC cold-rolled low-carbon steel flat products for cold forming.
5. AIST (Association for Iron & Steel Technology) Temper Mill & Flatness Best Practices.