How to Read a Baosteel Mill Test Certificate (MTC), Line by Line

Jay Zheng

Jay Zheng

29 окт. 2026 г.

How to Read a Baosteel Mill Test Certificate (MTC), Line by Line

In steel trading, everyone asks "how much per ton". At Baohui we say it differently: the quotation decides whether you can buy — the MTC decides whether you dare to use it.

The MTC (mill test certificate, or 产品质量证明书 / INSPECTION CERTIFICATE) is the single most important document attached to any steel plate. Below, we walk through a genuine Baosteel certificate field by field — a BS960E plate — and show how the same reading applies to any Baosteel grade, from NM400 wear plate to shipbuilding steel.

Genuine Baosteel inspection certificate for NM400 wear plate
A genuine Baosteel inspection certificate, supplied with every plate we deliver.

Step 1: Read the identity block — who made it and what it is

The header section of the certificate is the plate's household registration.

  • Manufacturer. On our example certificate, the manufacturer reads "总部 / CORE BASE" — Baoshan Iron & Steel Co., Ltd., Shanghai headquarters. That designation means the plate comes off Baosteel's core Baoshan production lines, the group's top-tier process and quality-control system. Certificates from the Wuhan base instead show "武汉钢铁有限公司 / Wuhan Iron & Steel Co., Ltd.". Both are Baowu Group mills.
  • Product name. "热轧后续热处理钢板" — hot-rolled plate, subsequently heat-treated. The delivery condition column spells it out: QT: quenched + tempered. The plate was not sold as-rolled; it went through hardening and tempering — the deep "fitness training" that refines the grain and unlocks its performance.
  • Grade. On our example: BS960E. The number is a promise — minimum yield strength of 960 MPa, ultra-high-strength structural steel. The letter is just as important: E means the steel keeps its toughness at -40 °C and will not turn glass-brittle in extreme cold.
  • Dimensions. Our example: 7.0 mm × 1800 mm × 12000 mm. A 7 mm plate at 960 MPa delivers an exceptional strength-to-weight ratio — the profile used on weight-critical special-vehicle frames and high-stress joints, where thinner plate carries larger loads.

Step 2: Read the three core tests

The dense table in the middle of the certificate is the plate's medical report. Three results matter most.

2.1 Strength — the tensile test (TENSILE TEST)

Key field: yield strength (ReH), the stress at which permanent deformation begins.

  • Requirement for BS960E: ≥ 960 MPa.
  • Measured on this certificate: 1,036 MPa (transverse, T) and 1,051 MPa (longitudinal, L).

Think of it like a battery rated at 10,000 mAh that actually tests at 10,500. The measured strength runs nearly 80 MPa above the floor — in service that means the equipment carries larger loads without permanent deformation, and designers keep an extra safety margin.

2.2 Cold resistance — the impact test (IMPACT TEST)

Key field: Charpy V-notch impact energy (KV2) at -40 °C — the hardest test for high-strength steel. Many steels that feel rock-hard at room temperature shatter like glass in winter. This test simulates Siberian, Nordic or high-altitude service.

  • Requirement for BS960E: ≥ 47 J.
  • Measured: 49 J, 47 J, 55 J — average 50 J.

Three consistent results across the heat show process stability: with sulfur and phosphorus held to very low levels (this heat's CEQ is only 0.54 %), composition control and heat treatment were precise. Even at -40 °C, the plate absorbs energy instead of cracking.

2.3 Workability — the bend test (BEND TEST)

Ultra-high-strength steel is useless if it cracks when your workshop bends it. The bend test reports OK, d = 5.0 a — bent 90° around a mandrel of five times the plate thickness (5 × 7 mm = 35 mm) with no cracks. Strength and formability together: that is what "刚/柔并济" looks like in numbers.

Step 3: Read the story behind the data

The footer tells you about consistency and provenance.

  • Heat stability. Our example certificate covers heat 15104893 — 3 plates, 3,561 kg total. The tensile values (1,036 / 1,051 MPa) and impact values (49 / 47 / 55 J) vary very little between plates from the same melt: the mill controlled that heat's melting, refining and rolling tightly.
  • Traceability. The purchaser field shows Shanghai Baosteel Steel Products Trading — the mill's official sales channel — with a named logistics consignee. The plate travelled a documented route from the mill into formal warehousing. Full traceability, no rebadging, no mixing.

The four-point check we run on every certificate

How to spot a genuine Baosteel MTC
CheckWhat to look forRed flag
1. ManufacturerBaoshan HQ ("CORE BASE/总部") or Wuhan Iron & SteelUnnamed or non-Baowu mills on a "Baosteel" certificate
2. Certificate numberBGSAI… (Baoshan) / BGBWI… (Wuhan) format, plausible dateRandom numbers, no date logic
3. Measured valuesTensile, hardness and impact filled in per heat, internally consistentBlank fields, or identical values across different heats
4. Party chainMill → official trading arm → named consignee → your supplierBroken or untraceable chain

Steel is not just cold metal — it is an industrial building block supported by precise data. To outsiders an MTC is an unreadable sheet of paper; to us at Baohui it is the foundation of every promise we make. We do not trade in talk — we answer with mill certificates. Every plate we ship, from NM400 wear plate to BS960E high-strength steel, carries its original certificate, one per heat.

Want a certificate with your next order? Contact Baohui Steel — and read our NM400 vs Hardox 400 comparison to see what real certificate data looks like in a specification debate.

Часто задаваемые вопросы

What is a mill test certificate (MTC)?

A mill test certificate — also called an inspection certificate or material test certificate — is the document a steel mill issues for each delivered batch, certifying the chemical composition and mechanical test results of that specific heat. For Baosteel plates it is titled '产品质量证明书 / INSPECTION CERTIFICATE' and carries a unique certificate number.

What do the letters in a Baosteel certificate number mean?

Certificate numbers starting with 'BGSAI' are issued by the Baoshan (Shanghai) headquarters base, and 'BGBWI' by Wuhan Iron & Steel. Together with the heat number and mill's number, they allow Baosteel to trace the plate back to the exact melt and rolling campaign.

What does 'QT: quenched + tempered' mean on the certificate?

QT means the plate was hardened by quenching and then tempered to achieve the specified strength-toughness balance — it was not sold as-rolled. Grades like BS960E or NM400 are delivered in the QT condition, which is what activates their high strength and fine grain structure.

What is the difference between ReH and Rm on the tensile test?

ReH is the yield strength — the stress at which the steel starts to deform permanently. Rm is the tensile (ultimate) strength — the maximum stress it can carry. Certificates typically show both, plus elongation (A or EL), which measures how much the steel stretches before breaking.

Why is -40 °C impact energy important?

Many high-strength steels are hard at room temperature but turn brittle in the cold. The Charpy V-notch impact test at -40 °C simulates Siberian, Nordic or high-altitude winter service: it proves the plate absorbs energy instead of shattering. The 'E' suffix in grades like BS960E means this -40 °C toughness is guaranteed.

How can I tell if a Baosteel MTC is genuine?

Check four things: (1) the manufacturer field names a real Baowu mill (Baoshan headquarters, Wuhan Iron & Steel, etc.); (2) the certificate number follows the BGSAI/BGBWI format with a plausible issue date; (3) the measured values (tensile, hardness, impact) are filled in per heat and internally consistent — blanks or copy-pasted values are a red flag; (4) the chain of parties (purchaser, consignee) is traceable from mill to your supplier.