JB/T 6401-2017 English PDF (JBT6401-2017)

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JB/T 6401-2017: Steel used for heavy roll forgings. Technical specification
JB/T 6401-2017
JB
MACHINERY INDUSTRY STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.85
J 32
Record number: 57817-2017
Replacing JB/T 6401-1992
Steel used for heavy roll forgings - Technical specification
ISSUED ON: JANUARY 9, 2017
IMPLEMENTED ON: JULY 1, 2017
Issued by: Ministry of Industry and Information Technology of the PRC
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Normative references ... 5 
3 Order requirements ... 5 
4 Manufacturing process ... 6 
4.1 Smelting ... 6 
4.2 Forging ... 6 
4.3 Heat treatment ... 6 
5 Technical requirements ... 6 
5.1 Chemical composition ... 6 
5.2 Mechanical properties ... 8 
5.3 Hardness ... 9 
6 Inspection rules and test methods ... 10 
6.1 Chemical composition analysis ... 10 
6.2 Tests of mechanical properties ... 10 
6.3 Hardness test ... 11 
7 Quality certificate ... 12 
8 Marking and packaging ... 12 
Steel used for heavy roll forgings - Technical specification
1 Scope
This Standard specifies the order requirements, manufacturing process, technical
requirements, inspection rules and test methods, quality certificate, marking and
packaging for heavy roll forgings, such as cold-rolled, hot-rolled work rolls and backup
rolls.
This Standard applies to the order, manufacture, and inspection of heavy roll forgings
(hereinafter referred to as forgings).
2 Normative references
The following documents are indispensable for the application of this document. For
the dated references, only the editions with the dates indicated are applicable to this
document. For the undated references, the latest edition (including all the amendments)
are applicable to this document.
GB/T 223 (all parts) Methods for chemical analysis of iron, steel and alloy
GB/T 228.1 Metallic materials - Tensile testing - Part 1: Method of test at room
temperature
GB/T 229 Metallic materials - Charpy pendulum impact test method
GB/T 13313 Methods of Shore and Leeb hardness testing for rolls
3 Order requirements
3.1 The purchaser shall specify in the order contract or technical agreement the purpose,
name, quantity, material designation, and delivery status of forgings; various technical
requirements and inspection items defined by both the supplier and the purchaser; and
inspection items other than those required by this Standard.
3.2 The purchaser shall provide the order drawing and the finishing drawing indicating
the dimension and technical requirements of the forgings.
3.3 When the purchaser has supplementary requirements, the supplementary
requirements shall be negotiated by both the supplier and the purchaser.
4 Manufacturing process
4.1 Smelting
Steel used for forgings shall be refined by ladle. Vacuum degassing shall be used as
much as possible, to reduce the content of harmful gases in steel. With the consent of
the purchaser, other methods such as out-of-furnace refining or electroslag remelting
that can meet the requirements of this Standard may also be used. The smelting method
of hot-rolled work rolls can also be negotiated by both the supplier and the purchaser.
4.2 Forging
4.2.1 Each ingot riser and both ends of the ingot tail shall have enough cut, to ensure
that the forgings are free from harmful defects, such as shrinkage cavities and severe
segregation.
4.2.2 Forgings shall be forged on a forging press with sufficient capacity, to ensure that
the entire section of the forging is fully forged; and the entire forging can be uniformly
structured, with a forging ratio of ≥3.
4.3 Heat treatment
Carry out heat treatment according to the delivery status of the forgings specified in the
order contract.
5 Technical requirements
5.1 Chemical composition
5.1.1 The analysis results of hot-rolled work rolls shall meet the requirements of Table
1.
5.1.2 The analysis results of cold-rolled work rolls shall meet the requirements of Table
2.
5.1.3 The analysis results of backup rolls shall meet the requirements of Table 3. When
multiple furnaces are poured together, the weight analysis results shall prevail.