GB/T 3278-2023Hot-rolled steel plates, sheets and strips for tools (English PDF)

Foreword

This document was issued on 7 September 2023 by the State Administration for Market Regulation; Standardization Administration of the PRC and takes effect on 1 April 2024.

It is a GB/T standard: recommended rather than compulsory, but it is the text a Chinese reviewer applies when assessing a submission.

1 Scope

GB/T 3278-2023 covers hot-rolled steel plate, sheet and strip supplied for making tools - how the product is classified and coded, what an order has to state, the size, shape and weight, the technical requirements beginning with designation and chemical composition, the test methods, the inspection rules, and the packaging, marking and quality certificate. Classification starts with edge state, cut edge or mill edge, and the order content clause lists what the contract has to carry: a reference to this document, the product name, and the further particulars a mill needs before it rolls anything. Dimensions, shape and permitted deviations are set out for material of nominal width from 600 mm upward, with the thickness deviation of single-rolled plate handled in its own right. Ordering tool material by grade alone is where the trouble starts, because plate that meets the composition but not the thickness or shape tolerance has to be machined back to size before it can be hardened, and metal removed at that stage is paid for twice, once as steel and once as machining. Written for steel mills, tool and die makers, stockholders and the inspectors who release incoming material.

This document stipulates the classification and code, order content, size, shape, weight,

technical requirements, test methods, inspection rules, packaging, marking and quality

certificate of hot-rolled steel plates, sheets and strips for tools.

This document applies to hot-rolled steel plates, sheets and strips for tools with a

nominal thickness not greater than 25 mm (hereinafter referred to as steel plates, sheets

and strips).

2 Normative references

The following documents are referred to in the text in such a way that some or all of

their content constitutes requirements of this document. For dated references, only the

version corresponding to that date is applicable to this document; for undated references,

the latest version (including all amendments) is applicable to this document.

GB/T 222, Permissible tolerances for chemical composition of steel products

GB/T 223.5, Steel and iron - Determination of acid-soluble silicon and total silicon

content - Reduced molybdosilicate spectrophotometric method

GB/T 223.11, Iron, steel and alloy - Determination of chromium content - Visual

titration or potentiometric titration method

GB/T 223.14, Methods for chemical analysis of iron, steel and alloy - The N-benzoy-

N-phenylhydroxylamine extraction photometric method for the determination of

vanadium content

GB/T 223.19, Methods for chemical analysis of iron, steel and alloy - The

neocuproine-chloroform extraction photometric method for the determination of

copper content

GB/T 223.23, Iron, steel and alloy - Determination of nickel content - The

dimethylglyoxime spectrophotometric method

GB/T 223.26, Iron, steel and alloy - Determination of molybdenum content - The

thiocyanate spectrophotometric method

GB/T 223.62, Methods for chemical analysis of iron, steel and alloy. The butyl

acetate extraction photometric method for the determination of phosphorus content

GB/T 223.63, Iron, steel and alloy - Determination of manganese content - Sodium

(potassium) periodate spectrophotometric method

GB/T 223.68, Methods for chemical analysis of iron, steel and alloy - The potassium

iodate titration method after combustion in the pipe furnace for the determination of

sulfur content

GB/T 223.69, Iron, steel and alloy - Determination of carbon contents - Gas-

volumetric method after combustion in the pipe furnace

GB/T 224, Determination of depth of decarburization of steels

GB/T 230.1, Metallic materials - Rockwell hardness test - Part 1: Test method

GB/T 231.1, Metallic materials - Brinell hardness test - Part 1: Test method

GB/T 247, General rule of package, mark and certification for steel plates (sheets)

and strips

GB/T 709-2019, Dimension, shape, weight and tolerance for hot-rolled steel strip,

plate and sheet

GB/T 1299-2014, Tool and mould steels

GB/T 4336, Carbon and low-alloy steel - Determination of multi-element contents -

Spark discharge atomic emission spectrometric method (routine method)

GB/T 8170, Rules of rounding off for numerical values & expression and judgment

of limiting values

GB/T 10561-2023, Steel - Determination of content of nonmetallic inclusions -

Micrographic method using standards diagrams

GB/T 13298, Inspection methods of microstructure for metals

GB/T 13302, Steel - Determination of area content of graphite-micrographic method

using diagrams

GB/T 17505, Steel and steel products - General technical delivery requirements

GB/T 20066, Steel and iron - Sampling and preparation of samples for the

determination of chemical composition

GB/T 20123, Steel and iron - Determination of total carbon and sulfur content

Infrared absorption method after combustion in an induction furnace (routine

method)

GB/T 20125, Low-alloy steel. Determination of multi-element contents. Inductively

coupled plasma atomic emission spectrometric method

3 Terms and definitions

No terms and definitions need to be defined in this document.

4 Classification and code

4.1 Steel plates, sheets and strips, by edge state, are classified into:

a) cut edge, EC;

b) mill edge, EM.

4.2 Continuous-rolled steel plates, sheets and strips, by thickness accuracy, are

classified into:

a) ordinary thickness accuracy, PT.A;

b) higher thickness accuracy, PT.B.

4.3 Steel plates, sheets and strips, by surface treatment method, is classified into:

a) rolled surface, SR;

b) acid-pickled surface, SA.

5 Order content

5.1 The order contract or order form includes the following:

a) a reference to this document;

b) product name (steel plate or steel strip);

c) designation;

d) specifications and size, shape and accuracy;

e) delivery state;

f) edge state;

g) surface treatment method;

h) weight;

i) special requirements.

5.2 When it is not specified in the order contract or order form, the following provisions

shall apply:

a) Where the surface treatment method is not indicated, the product shall be supplied

with rolled surface;

b) Single-rolled steel plates delivered with rolled surfaces shall be supplied in the

state of Class A thickness tolerance and cut edge as specified in GB/T 709-2019;

continuous-rolled steel plates, sheets and strips shall be supplied in the state of

ordinary thickness accuracy and mill edge;

c) For steel plates, sheets and strips delivered with acid-pickled surfaces, if the

thickness accuracy and edge state are not specified, they shall be supplied in the

state of higher thickness accuracy and cut edge.

6 Size, shape and weight

6.1 The size, shape and allowable deviation of steel plates, sheets and strips with a

nominal width of not less than 600 mm shall comply with the following requirements:

a) The thickness allowable deviation of single-rolled steel plates shall comply with

the requirements in Table 2 of GB/T 709-2019, and the thickness allowable

deviation of continuous-rolled steel plates, sheets and strips shall comply with the

requirements in Table 4 of GB/T 709-2019;

b) The unevenness of single-rolled steel plates shall comply with the requirements

in Table 10 of GB/T 709-2019, and the unevenness of continuous-rolled steel

plates shall comply with the requirements corresponding to “the specified

minimum yield strength Re is greater than 300 MPa” in Table 11 of GB/T 709-

2019;

c) The allowable deviations in other sizes and shapes of steel plates, sheets and strips

shall comply with the provisions of GB/T 709-2019.

6.2 The size, shape and allowable deviation of steel strips with a nominal width less

than 600 mm shall comply with the provisions of Appendix A. Special requirements

from the buyer, if any, shall be determined through negotiation between the supplier

and the buyer and stated in the contract.

6.3 Steel plates, sheets and strips are delivered according to actual weight.

7 Technical requirements

7.1 Designation and chemical composition

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