1. Measured-value comparison tool (file import / screenshot OCR)
Paste a screenshot of the mill certificate (MTC)straight in with Ctrl+V, orimport a PDF / image / txt / csv file— the grade and measured values are recognised automatically and compared item by item with the standards library. Without a file, pick a grade in the dropdown on the right and click "Enter test values manually" to type the values straight in.Check the OCR result yourself before judging; rows with more than one condition (e.g. annealed and quenched-and-tempered hardness side by side) are flagged only, never judged automatically.
Tip: press Ctrl+V anywhere in this area to paste a screenshot, or paste the text into the box below first.
2. Quick grade lookup
Type a grade — Chinese or foreign, old or new — and get composition, tensile and yield strength, elongation and hardness straight away. Condition suffixes and standard prefixes work too, e.g. 6061-T6, SUS304, EN 1.4301, Q345B (recognised as Q355). 34 common materials are covered (including ductile iron QT and grey iron HT).
3. Carbon structural steels (GB/T 700, GB/T 1591)
4. Quality carbon and alloy structural steels (GB/T 699, GB/T 3077, GB/T 1222)
5. Stainless steels (GB/T 20878, GB/T 4237, GB/T 1220)
6. Aluminium alloys (GB/T 3190, GB/T 3880, GB/T 6892)
7. Copper alloys (GB/T 5231)
8. Chinese and international grade equivalents
Equivalent grades are approximate only: composition limits, mechanical values and inspection rules differ between countries, so an equivalent gradecannot replace the inspection required by the standard on the drawing. For export orders, acceptance rests on the standard named on the drawing or order (ASTM/JIS/EN/DIN) plus the measured values in the mill certificate (MTC — EN 10204 3.1 preferred).
9. Incoming material acceptance
- Check the MTC first, then the standard: for every lot, confirm the heat number on the certificate matches the stencil or stamp on the material, then check composition and mechanical values against the standard.
- Composition check: for critical parts, re-check the main elements (C, Si, Mn, Cr, Ni, Mo, Cu and so on) on site with an optical emission spectrometer and compare them with the standard ranges.
- Mechanical check: sample each lot for tensile testing (GB/T 228.1 / ASTM E8) and compare tensile, yield (Rp0.2 or ReL) and elongation; test hardness per GB/T 231.1 (HB) or GB/T 230.1 (HRC).
- Don't misread the condition: the same grade behaves very differently in different heat-treatment conditions — 6063 T5 versus T6, 45 steel normalized versus quenched and tempered, stainless solution annealed versus annealed. Confirm the delivery condition before accepting.
- Stainless: check magnetism and corrosion resistance:304/316 in the solution-annealed condition are essentially non-magnetic (slight magnetism after cold work is acceptable); 316 with molybdenum resists chlorides better than 304 without it, so Mo is the key element on the purchase order.
- Aluminium extrusions: read the temper code: T5 (air quenched plus artificial ageing) and T6 (water quenched plus artificial ageing) differ in strength; 6063-T6 needs a tensile strength of at least 205 MPa — anything lower is a reject.
- Surface and dimensions: hot-rolled steel may carry mill scale, cold-rolled sheet (SPCC/DC01) must have no rust spots; sample the anodic film thickness on aluminium per GB/T 8013 (normally ≥ 10 μm).
10. Sheet tempers (hardness grades): suggested hardness ranges and how they are obtained
Sheet orders often say "soft / half hard / full hard", which maps to the aluminium O / H tempers (GB/T 16475) and to the soft-to-hard grading of steel sheet. Check hardness and mechanical values against the stated temper on receipt, so half-hard stock is not deep drawn as if soft (it cracks) and full-hard stock is not bent (it snaps).
1) Aluminium temper codes (the second digit sets the hardness grade)
| Temper | Meaning / how it is obtained | Hardness level | Typical use |
|---|---|---|---|
| O (soft) | fully annealed (soaked at about 345 °C then slow cooled), all cold work removed | lowest | deep drawing, drawn parts, heavy subsequent bending |
| H12 / H22 / H32 | 1/4 hard. H1x = strain-hardened only; H2x = strain-hardened and partially annealed; H3x = strain-hardened and stabilised (common in the 5xxx series) | low | lightly loaded sheet metal that still needs some forming |
| H14 / H24 / H34 | half hard (1/2 H), reached with about 20–30% cold reduction (depending on the series) — the best balance of strength and bendability | medium | the most common temper for sheet metal parts, bends and light stamps well |
| H16 / H26 / H36 | 3/4 hard, with more cold reduction | high | flat panels and covers with little forming |
| H18 / H28 / H38 | full hard, about 55–75% cold reduction (cumulative after annealing) | highest | not bent (it cracks easily) — flat panels and backing plates only |
| T4 | solution treatment plus natural ageing (6xxx/7xxx) | — | formed first, then aged — age hardening applies |
| T6 | solution treatment plus artificial ageing | — | the strongest commonly used temper in 6xxx/7xxx |
| T5 | hot extruded, cooled and then artificially aged (usual for extrusions) | — | 6063-T5 extrusion |
2) 5052 by temper (half hard = H34, the most common)
| Temper | Suggested hardness (HB ≈) | Tensile Rm (MPa) | Yield Rp0.2 (MPa) | Elongation A (indicative) | How obtained |
|---|---|---|---|---|---|
| 5052-O | 45–55 | 170–215 | ≥ 65 | ≥ 16% | fully annealed (about 345 °C) |
| 5052-H32 | 55–65 | 215–265 | ≥ 160 | ≥ 7% | cold rolled (about 1/4) and stabilised |
| 5052-H34 (half hard) | 63–72 | 235–285 | ≥ 180 | ≥ 7% | cold rolled (about 1/2) and stabilised |
| 5052-H36 | 70–78 | 255–305 | ≥ 200 | ≥ 3% | cold rolled (about 3/4) and stabilised |
| 5052-H38 | 75–84 | ≥ 270 | ≥ 220 | ≥ 3% | cold rolled full hard and stabilised |
3) Other common sheet tempers (hardness is indicative; accept against the MTC and the order standard)
| Grade / temper | Suggested hardness (HB ≈) | Tensile Rm (MPa) | How obtained |
|---|---|---|---|
| 1060-O | 15–19 | 60–100 | fully annealed — deep drawing, nameplates |
| 1060-H14 | 25–30 | 110–145 | cold rolled half hard |
| 1060-H18 | 33–38 | ≥ 130 | cold rolled full hard, must not be bent |
| 6061-O | 25–35 | ≤ 150 (typically 110–150) | annealed, T6 after forming |
| 6061-T4 | 60–70 | ≥ 180 (YS≥110) | solution treated plus natural ageing |
| 6061-T6 | 90–100 | ≥ 290 (YS≥240) | solution treated (about 530 °C, water quench) plus artificial ageing (about 175 °C) |
| 6063-T5 (extrusion) | 60–70 | ≥ 160 (YS≥110) | extruded, air quenched and artificially aged |
| 6063-T6 (extrusion) | 70–80 | ≥ 205 (YS≥170) | extruded, water quenched and artificially aged |
| 2A12 (LY12)-T4 | 95–110 | ≥ 390–425 (YS≥255–275) | solution treated plus natural ageing (the usual duralumin temper) |
| 7075-T6 | 145–160 | ≥ 530 (YS≥460) | solution treated plus artificial ageing — super-duralumin |
| H62 (brass) soft / half hard | 55–75 (soft) / 90–120 (half hard, HV) | ≥ 294 (soft) / ≥ 372 (half hard) | annealed (soft) / cold reduced about 20–30% (half hard) |
| QSn6.5-0.1 soft / hard | about 80–100 (soft, HV) / ≥ 180 (hard, HV) | ≥ 315 (soft) / ≥ 490–637 (hard) | annealed / strain hardened (hard for spring contacts) |
4) Soft-to-hard grading of cold-rolled steel sheet (SPCC/SPCD/SPCEN)
| Sheet condition | Suggested hardness (HV ≈) | Cold reduction (indicative) | How obtained |
|---|---|---|---|
| soft (SPCEN / deep-drawing grade) | 85–110 | 0 (temper rolled after annealing) | batch or continuous annealing, for deep drawing |
| 1/4 hard | 110–140 | about 10–15% | light cold rolling after annealing |
| half hard (1/2H) | 140–170 | about 20–35% | medium cold reduction; balances bending and strength |
| full hard (SPCC-H) | ≥ 180 (HRB ≥ 85) | about 45% and above | heavy cold reduction, no further annealing |
Choosing the hardness method: ① plate 10 mm and thicker: Brinell HB (large indentation, most representative); thin sheet: Vickers HV (low load) or Rockwell (HRB for thin steel, HRF/HR15T for thin aluminium); extruded aluminium on site: Webster hardness tester (W-20, 6063-T5 reads about 8–10); coated parts: surface Vickers only, or microhardness per GB/T 9790; ② hardness scales cannot be compared numerically — convert per GB/T 1172 (approximate only); ③ cold-rolled sheet is directional, so spread the test points (edge and centre, head and tail) and take representative values; ④ when a bend cracks, first check that the temper is right (H38 full hard must not be bent), then the angle between the bend line and the rolling direction (bending along the rolling direction cracks — bend across it or use a larger radius); ⑤ for deep drawing use O or H32 and softer; large draw ratios require O.