GB/T 15712-2008 in English

《GB/T 15712-2008非调质机械结构钢》由TC183（全国钢标准化技术委员会）归口，TC183SC16（全国钢标准化技术委员会特殊钢分会）执行，主管部门为中国钢铁工业协会。
本标准１９９５年１０月首次发布。本标准规定了非调质机械结构钢的尺寸、外形及允许偏差、技术要求、试验方法、检验规则、包装、标志及质量证明书等。本标准代替ＧＢ／Ｔ１５７１２―１９９５ 《非调质机械结构钢》。本标准与ＧＢ／Ｔ１５７１２―１９９５相比主要变化如下：
―――英文名称修改为：Ｍｉｃｒｏａｌｌｏｙｅｄｍｅｄｉｕｍｃａｒｂｏｎｓｔｅｅｌｓ（见封面和３．１）；
―――修改了“非调质机械结构钢”的定义（见第３章）；
―――将“切削加工用钢”修改为“直接切削加工用钢”（见第４章）；
―――取消切削加工用钢牌号表示方法中的“Ｙ”，用尾部加“Ｓ”表示含硫钢，即牌号表示方法“ＹＦ．．．”修改为“Ｆ．．．Ｓ”（见表１）；
―――增加了“订货内容”（见第５章）；
―――增加了银亮钢及相关要求（见第１章，６．２，７．８．３等）；
―――增加了Ｆ３０ＭｎＶＳ、Ｆ３８ＭｎＶＳ、Ｆ４９ＭｎＶＳ 和Ｆ１２Ｍｎ２ＶＢＳ 等牌号及相关要求，将ＹＦ４５Ｖ 与Ｆ４５Ｖ、ＹＦ３５ＭｎＶ 与Ｆ３５ＭｎＶＮ、ＹＦ４０ＭｎＶ 与Ｆ４０ＭｎＶ 分别合并为Ｆ４５ＶＳ、Ｆ３５ＭｎＶＳ 和Ｆ４０ＭｎＶＳ（见表１）；
―――增加了直接切削加工用钢成分可以协商的内容（见７．１．１）；
―――化学成分增加了“经供需双方协商，可以用铌或钛代替部分或全部钒含量。在部分代替情况下，钒的下限含量应由双方协商”（见７．１．２）；
―――化学成分允许偏差按ＧＢ／Ｔ２２２―１９８４表２列出，并补充了硫含量和氮含量的允许偏差（１９９５年版的６．１．２；本版的表２）；
―――冶炼方法修改为由供方选择（１９９５年版的６．２；本版的７．２）；
―――钢材交货状态取消了锻制状态，增加了银亮状态交货（１９９５年版的６．３；本版的７．３）；
―――热压力加工用钢的力学性能由基本保证项目改为协议保证项目；
―――取消了“淬火断口”检验低倍组织（１９９５年版的６．５．１；本版的７．５．１）；
―――热压力加工用钢的脱碳层检验由协议保证项目修改为基本保证项目（１９９５年版的６．７；本版的７．６．１）；
―――非金属夹杂物由协议保证项目修改为基本保证项目，并将Ａ 类细系放宽１ 级，Ｂ 类加严０．５级，ＤＳ类提供实测数据（１９９５年版的６．６；本版的７．７）；
―――增加本标准牌号与１９９５版标准牌号和ＩＳＯ１１６９２标准牌号的对照（见附录Ａ）。

1 Scope

This standard specifies the definition, classification, order contents, dimension, appearance and permissible deviation, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of microalloyed medium carbon steels.
This standard is applicable to hot-rolled steel and bright steel which are belong to microalloyed medium carbon steels.

2 Normative References

The following standards contain provisions which, through reference in this standard, constitute provisions of this standard. For dated references, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, the parties who enter into agreement according to this standard are encouraged to study whether the latest editions of these documents apply. For undated references, the latest edition applies to this standard.
GB/T 223.3 Methods for Chemical Analysis of Iron, Steel and Alloy - Diantipyrylmethane Phosphomolybdate Gravimetric Method for the Determination of Phosphorus Content
GB/T 223.4 Methods for Chemical Analysis of Iron, Steel And Alloy - Volumetric Method for Determination of Manganese Content by Ammonium Nitrate Oxidation
GB/T 223.5 Methods for Chemical Analysis of Iron, Steel and Alloy - Reduced Molybdosilicate Spectrophotometric Method for the Determination of Acid-soluble Silicon Content
GB/T 223.11 Methods for Chemical Analysis of Iron, Steel and Alloy - Ammonium Persulfate Oxidation Volumetric Method for the Determination of Chromium Content
GB/T 223.12 Methods for Chemical Analysis of Iron, Steel and Alloy - Sodium Carbonate Separation-diphenyl Carbazide Photometric Method for the Determination of Chromium Content

GB/T 223.13 Methods for Chemical Analysis of Iron, Steel and Alloy - Ammonium Ferrous Sulfate Titration Method for the Determination of Vanadium Content
GB/T 223.14 Methods for Chemical Analysis of Iron, Steel and Alloy - N-benzoy-N-phenylhydroxylamine Extraction Photometric Method for the Determination of Vanadium Content
GB/T 223.16 Methods for Chemical Analysis of Iron, Steel and Alloy - Chromotropic Acid Photometric Method for the Determination of Titanium Content
GB/T 223.17 Methods for Chemical Analysis of Iron Steel and Alloy - Diantipyrylmethane Photometric Method for the Determination of Titanium Content
GB/T 223.18 Methods for Chemical Analysis of Iron, Steel and Alloy - Sodium Thiosulfate Separation Iodimetric Method for the Determination of Copper Content
GB/T 223.19 Methods for Chemical Analysis of Iron Steel and Alloy - Neocuproine-chloroform Extraction Photometric Method for the Determination of Copper Content
GB/T 223.23 Methods for Chemical Analysis of Iron, Steel and Alloy - Dimethylglyoxime Spectrophotometric Method for the Determination of Nickel Content
GB/T 223.24 Methods for Chemical Analysis of Iron, Steel and Alloy - Extraction Separation - Dimethylglyoxime Spectrophotometric Method for the Determination of Nickel Content
GB/T 223.37 Methods for Chemical Analysis of Iron Steel and Alloy - Indophenal Blue Photometric Methods for the Determination of Nitrogen Content after Distillation Separation
GB/T 223.40 Iron Steel and Alloy - Determination of Niobium Content by the Sulphochlorophenol S Spectrophotometric Method
GB/T 223.53 Methods for Chemical Analysis of Iron, Steel and Alloy - Flame Atomic Absorption Spectrophotometric Method for the Determination of Copper Content
GB/T 223.54 Methods for Chemical Analysis of Iron, Steel and Alloy - Flame Atomic Absorption Spectrophotometric Method for the Determination of Nickel Content
GB/T 223.58 Methods for Chemical Analysis of Iron, Steel and Alloy - Sodium Arsenite-sodium Nitrite Titrimetric Method for the Determination of Manganese Content
GB/T 223.59 Methods for Chemical Analysis of Iron, Steel and Alloy - Reduced Molybdoantimonyl Phosphoric Acid Photometric Method for the Determination of Phosphorus Content
GB/T 223.60 Methods for Chemical Analysis of Iron, Steel and Alloy - Perchloric Acid Dehydration Gravimetric Method for the Determination of Silicon Content

GB/T 223.61 Methods for Chemical Analysis of Iron, Steel and Alloy - Ammonium Phosphomolybdate Volumetric Method for the Determination of Phosphorus Content
GB/T 223.62 Methods for Chemical Analysis of Iron, Steel and Alloy - Butyl Acetate Extraction Photometric Method for the Determination of Phosphorus Content
GB/T 223.63 Methods for Chemical Analysis of Iron, Steel and Alloy – Sodium (Potassium) Periodate Photometric Method for the Determination of Manganese Content (GB/T 223.63-1998, neq ISO R 629)
GB/T 223.64 Methods for Chemical Analysis of Iron, Steel and Alloy - Flame Atomic Absorption Spectrometric Method for the Determination of Manganese Content

Foreword i
1 Scope
2 Normative References
3 Terminologies and Definitions
4 Classifications
5 Order Contents
6 Shape, Dimension and Tolerance
7 Technical Requirements
8 Test Method
9 Inspection Rules
10 Packaging, Marking and Quality Certificate
Appendix A (Informative) Comparison of Designations in This Standard and Those in Edition 1995 and ISO
Appendix B (Informative) Technical Differences Between This Standard and ISO 11692:1994 and the Reasons