A Field Note on the Temper Rolling Mill: What Buyers Quietly Ask

Steel customers rarely talk about it on LinkedIn, but the last 1–2% of thickness reduction can make or break downstream yield. That’s where a Temper Rolling Mill (often called a temper/skin-pass line) earns its keep. In practice, it removes yield-point elongation, stabilizes the grain, and gives the coil a predictable surface topography so your press shop doesn’t fight orange peel or Lüders bands.

What it actually does (and why it matters)

• Eliminates yield terrace; improves deep-draw performance and formability.
• Tunes surface roughness (Ra) for paintability, adhesion, and lube retention.
• Improves flatness/straightness; cuts coil set. Operators sleep better.
• Soft reduction to nudge thickness and mechanical properties when needed.

Origin note: the Temper Mill discussed here is engineered in Beijing (No.1518, LAR Valley Int’l, Guang’anmen Avenue, Xicheng District, 100055). I visited once; tidy shop floor, lots of surface metrology gear—promising sign.

Typical process flow (real-world)

Entry coil → end shear/welder → alkaline cleaning → temper stand (4‑Hi or 6‑Hi) → tension leveler → electrostatic oiler → inspection → exit recoiler. Materials include low-carbon, IF steels, tinplate substrate, some ferritic stainless, even HSS in cautious passes.

Testing and QA checkpoints usually reference ISO 6892‑1 for tensile (proof stress elimination check), ISO 4287/4288 for Ra/Rz, EN 10131 for flatness, plus coil hardness (HV/HB) and off-line cup-draw where automotive is in the mix. Service life? The line frame is ≈20+ years with proper upkeep; work-roll campaigns vary but regrind intervals often run 2–6 weeks depending on steel and Ra targets.

Product specs (typical, project-dependent)

Parameter	Spec (≈)	Notes
Input thickness	0.2–3.0 mm	Application-specific
Width	600–1,850 mm	Wider lines on request
Line speed	300–1,200 m/min	Depends on Ra, yield strength
Temper reduction	0.5–2.0%	Soft reduction possible
Surface roughness	Ra 0.3–2.5 μm	Shot/EDT roll textures
Flatness	≤ 8 I-units (around)	Per EN 10131 methods

Where it shines

Automotive body and chassis, white goods panels, crown caps/tinplate, construction cladding, tube strip. Many customers say the biggest win is consistency—press-room feedback gets… quieter. Which is good.

Vendor snapshot (short list)

Vendor	Edge	Certs	Lead Time
YWLX (Beijing)	Strong Ra control, flexible upgrades	ISO 9001; CE on subsystems	≈ 6–10 months
EU Maker M	High automation, deep analytics	ISO 9001/14001	≈ 10–14 months
Domestic S	Cost-effective, standard configs	ISO 9001	≈ 5–8 months

Customization & controls

Options I’ve seen work well: 6‑Hi stand for harder grades, EDT texturing, laser flatness gauge, automatic roll changing, closed-loop elongation control, vision surface inspection, enhanced oiler for anti-fingerprint films. Integration with MES/Level 2 brings better coil genealogy and traceable Ra/elongation data—auditors love that.

Case notes and test data

A Southeast Asia line processing 0.6–1.2 mm IF steel reported elimination of YPE with temper reductions of 0.8–1.2%; elongation uniformity improved ≈2–4%, Ra held at 1.1 ± 0.2 μm (ISO 4287). Downstream rejection dropped by ~38% in the first quarter. To be honest, that’s better than I expected.

Industry trends

Three things: higher-speed automation, live flatness/Ra feedback, and eco-fluids with tighter cleanliness specs. Also, more requests to run AHSS grades—with careful roll texture and tension control, a Temper Rolling Mill can handle them, within reason.

Citations

1. ASTM A568/A568M – General Requirements for Steel Sheet [astm.org]
2. ISO 6892‑1 – Metallic materials — Tensile testing [iso.org]
3. ISO 4287/4288 – Surface texture: profile method [iso.org]
4. EN 10131 – Cold rolled uncoated low carbon steel flat products — Tolerances [standards bodies]
5. AIST – Temper/Skin-Pass Mill Technology Overviews [aist.org]