GB/T 6414-2017Castings -- Dimensional tolerances and geometrical tolerances and machining allowances (English PDF)

Foreword

This Standard is drafted in accordance with the rules given in GB/T 1.1-2009.

This Standard replaces GB/T 6414-1999 "Castings - System of dimensional

tolerances and machining allowances". Compared with GB/T 6414-1999, the

main technical changes of this Standard are as follows.

- Modify some tolerance values of dimensional casting tolerances;

- Modify the tolerance grades that can be achieved during mass production

of various alloy castings in Table A.1;

- ADD Table 1 Abbreviated terms;

- ADD Table 3~Table 7;

- Modify the tolerance grades of Table A.1 and Table A.3;

- Delete the previous Annex C; ADD new Annex C, D and E.

This Standard uses the redraft law to modify and adopt ISO 8062-3.2007

"Geometrical product specifications (GPS) - Dimensional and geometrical

tolerances for moulded parts - Part 3.General dimensional and geometrical

tolerances and machining allowances for castings".

Compared with ISO 8062-3.2007, this Standard has many adjustments in

structure. Annex E lists the comparison of clause-subclause number between

this Standard and ISO 8062-3.2007.

The technical differences between this Standard and ISO 8062-3.2007 and

their reasons are as follows.

- ADD the nominal dimension of casting and illustration in Clause 3 Terms

and definitions;

- ADD Clause 4 Dimension indication;

- ADD Clause 5 Tilt elements;

- ADD the graphical description of required machining allowance in Clause

10.

This Standard has made the following editorial change.

- CHANGE the standard name to "Castings - Dimensional tolerances and

geometrical tolerances and machining allowances".

This Standard was proposed by and shall be under the jurisdiction of National

Technical Committee 54 on Foundry of Standardization Administration of China

(SAC/TC 54).

Responsible drafting organization of this Standard. Shenyang Research

Institute of Foundry.

Participating drafting organizations of this Standard. Anhui Research Institute

of Mechanical Science, Anhui Yingliu Group Huoshan Casting Co., Ltd., Hefei

Jianghuai Casting Co., Ltd., Anhui Shenjian Technology Co., Ltd., CRRC

Qishuyan Institute Co., Ltd., Tianrun Crankshaft Co., Ltd., CITIC Dicastal Co.,

Ltd., Tederic Heavy Machinery Co., Ltd., Cixi Huili Machinery & Electric Co.,

Ltd., Henan Huaihai Jingcheng Industrial Technology Co., Ltd., Hebei Jianzhi

Casting Group Ltd., Nanchang University, Dongfeng (Shiyan) Nonferrous

Casting Co., Ltd.

Main drafters of this Standard. Zhang Yin, Liu Dongmei, Wang Fang, Du Yingliu,

Qian Kuncai, Jiang Tianfang, Li Yong, Zhao Yongzheng, Pei Bing, Wei

Chuanying, Cong Jianchen, Cong Hongri, Bai Bangwei, Xie Mingli, Li Lifeng,

Luo Yu, Liu Quanrong, Song Liang, Cheng Kai, Chang Wei, Ren Jiuhong, Li

Guolin, Yang Zhaoling, Ye Han.

The previous editions of the standard replaced by this Standard were released

as follows.

- GB/T 6414-1986; GB/T 6414-1999.

Castings - Dimensional tolerances and geometrical

tolerances and machining allowances

1 Scope

This Standard specifies the terms and definitions of dimensional tolerances,

geometrical tolerances and machining allowances of castings, dimension

indication method, dimensional casting tolerance grades, geometrical tolerance

grades, required machining allowance grades and their indications on drawings.

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 131 Geometrical Product Specifications (GPS) - Indication of Surface

texture in technical Product documentation

3 Terms and definitions

The terms and definitions defined in GB/T 5611 and the following ones apply to this document.

The taper on the pattern or core box wall parallel to the drawing direction, in

order to make the pattern easy to be taken out of the casting mould or the core

escape from the core box.

4 Dimension indication

Except for wall thickness dimensioning (a dimension chain consisting of two

dimensions is allowed), chain dimensioning shall be avoided.

5 Tilt elements

6 Abbreviated terms

Abbreviated terms are given in Table 1.

7 Tolerance grades

The nominal dimension used in Table 3~Table 6 is the largest nominal

dimension of the casting structure. The nominal dimension of the fillet may be

ignored and does not need to be indicated separately.

For general orientation tolerances, a datum system shall be specified on the

drawing and identified by the indication "GB/T 6414-2017 DS" on the drawing.

Indication example.

8 Surface mismatch (SMI)

9 Wall thickness tolerance

Unless otherwise specified, the wall thickness tolerances from DCTG1 to

DCTG15 shall be one grade coarser than the general tolerances of other

dimensions. For example, on a drawing with a general tolerance grade of

DCTG10, the wall thickness tolerance shall be DCTG11.

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