Cold Rolled Coil (CRC)

1. Definition

Cold rolled coil (CRC) is produced by reducing pickled hot-rolled strip at ambient temperature on tandem or reversing cold mills. High pressure sets precise thin gauges, smoother surfaces, and altered mechanical properties through work hardening.

2. Process Route

1. Start from HRC.
2. Pickle to remove mill scale.
3. Cold reduce to target thickness (large % reduction common).
4. Optional anneal (batch or continuous) for formable tempers.
5. Temper / skin-pass roll for flatness, finish, and strain-age control.
6. Inspect, oil, and coil.

3. Full Hard and Other Tempers

Full hard CRC is the as-cold-reduced product without anneal—high strength/hardness, limited formability. Quarter-hard, half-hard, and skin-passed/annealed conditions offer stepped ductility. Supplier notes sometimes illustrate that full hard may only tolerate shallow bends while skin-passed annealed sheet supports right-angle forming—always verify with your grade data.

4. Annealing Role

Annealing recrystallizes the cold-worked structure, lowers residual stress, and restores ductility for drawing and complex forming. Without it, CRC remains in the work-hardened full-hard state.

5. CRC vs HRC for Roll Forming

• CRC: thin gauges, better surface, tighter tolerance—base for many coated building coils
• HRC: thicker, lower cost feedstock for non-cosmetic structural roll forming

6. Buying Checklist

1. Standard / grade / temper.
2. Thickness, width, surface finish class.
3. Yield, tensile, elongation on MTC.
4. Oiled vs dry; packaging for corrosion.
5. Whether the coil is substrate for later coating.

7. Boundaries

• CRC ≠ hot-rolled pickled coil.
• Full hard ≠ annealed drawing quality.
• No price claims on this page.

Buyer / Engineer FAQ

Is full-hard CRC good for deep roll-form ribs?

Usually poor—limited ductility. Prefer annealed / appropriate temper unless the part truly needs full-hard strength and gentle bends.

Why temper roll after anneal?

To improve flatness/surface finish, eliminate yield-point elongation issues, and reduce stretcher-strain risk in forming.

Typical CRC thickness?

Market discussions often place regular CRC roughly from ~0.18 mm up to ~3 mm, with bulk volumes in thinner gauges—always order the exact thickness you form.

CRC vs coated GI/PPGI?

CRC is often the substrate before galvanizing or painting. Building roll formers frequently run coated coil, not bare CRC.

Does cold reduction raise strength?

Yes—work hardening during cold reduction raises strength/hardness and lowers ductility until annealing resets the structure.

Can CRC replace HRC 1:1?

Only if thickness, strength, surface, and cost all fit. Do not swap without checking the flower and customer surface requirements.

Plant Practice Notes

Lead RFQ conversations with measurable acceptance criteria, not adjectives. Document whether a number comes from a mill certificate, a plant trial, or a published standard table.

When two heats of the same grade behave differently, pull certificates and process logs before rebuilding tooling. Most mystery forming issues are heat-to-heat property or lubrication shifts.

• Keep units consistent (MPa vs ksi; mm vs in).
• Record test methods when citing formability indices.
• Attach heat numbers to scrap photos and CAPA files.
• Separate design minimums from actual forming windows.
• Update SOPs when a new grade or coating family is introduced.
• Train receiving to stop on out-of-window certificates.

1. Define the decision this page supports (buy / form / inspect / redesign).
2. List the three certificate or process fields that matter most.
3. List shop symptoms that should trigger a re-read of this page.
4. Name the next specialist encyclopedia page to open.
5. File the lesson learned after each coil-related incident.

Auditors respond better to traceable certificate fields than to verbal grade nicknames. Keep EN 10204 type and heat mapping visible at receiving.

After any coil change that moves yield by a large step, expect springback and load changes even when thickness is identical.

Do not invent universal machine kW or m/min values on materials encyclopedia pages.

Extended Notes

State temper clearly: full-hard, quarter-hard, or annealed/temper-passed CRC. Full-hard coils raise load and crack risk on the same flower that ran soft CRC.

Surface finish and thickness tolerance drive paint and roll-gap decisions—pull both from the certificate, not only yield.

• Watch slit-edge condition; CRC edges can initiate cracks on tight bends.
• After temper-mill or skin-pass changes, expect yield and springback shifts.