This standard specifies the value, determination method and inspection rules of casting weight tolerance. This standard is applicable to various metal and alloy castings produced by sand casting, metal mold casting, pressure casting, low pressure casting and investment casting. GB/T 11351-1989 Casting Weight Tolerance GB/T11351-1989 Standard Download Decompression Password: www.bzxz.net

National Standard of the People's Republic of China
Mass tolcrances for castings1 Subject content and scope of applicationwww.bzxz.net
GB/T 11351 89
This standard specifies the value, determination method and inspection rules of the weight tolerance of castings (hereinafter referred to as weight tolerance). This standard is applicable to various metal and alloy castings produced by sand casting, metal mold casting, pressure casting, low pressure casting and investment casting.
This standard is used in conjunction with GB6414-86 "Dimensional Tolerances of Castings". 2 Terminology
2.1 Nominal weight
Nominal weight is the reference weight including mechanical addition allowance and other process allowances, which is used as the weight to measure the weight of the casting to be inspected. 2.2 Casting weight tolerance
The allowable value of the casting weight variation in units of percentage of the nominal weight of the casting. 2.3 Weight tolerance grade
Determine the level of the degree of the weight tolerance of the casting. 3 Basic regulations
The code for weight tolerance is represented by the letters \MTI. There are 16 weight tolerance grades, MT1 to MT16. The total value of weight tolerance is listed in T3.1
Note: 1) The letters \MT\ stand for "Mass tolerances\Abbreviation of weight tolerance prefix. 3.2 Determination of nominal weight of castings.
3.2.1 In batch and mass production, no less than 10 castings shall be randomly selected from the first batch of qualified castings recognized by both the supply and demand parties, and the average value of the actual weighed weight shall be used as the nominal weight. 3.2.2 In small batch and single piece production, the calculated weight or the actual weighed weight of any qualified casting recognized by both the supply and demand parties shall be used as the nominal weight.
3.2.3 The actual weighed weight of the standard sample shall be used as the nominal weight. 3.3 For the corresponding weight tolerance grade, the weight tolerance value shall be selected from Table 1 according to the range of the nominal weight. 3.4 For castings produced in batch and mass production, the weight tolerance grade shall be selected according to Table 2, and for small batch and single piece production For castings, the weight tolerance grade should be selected according to Table 3, and the weight tolerance should be selected in correspondence with the dimensional tolerance. For example: the dimensional tolerance is CT10, the weight tolerance is MT10, 3.5 Generally, the lower deviation and upper deviation of the weight tolerance are the same, and the lower deviation can also be selected two levels higher than the upper deviation. For example: the weight + deviation is MT10, and the lower deviation is MT8.
3.6 When there are special requirements, the weight tolerance can be agreed upon by the supply and demand parties, but it should be indicated in the drawings or technical documents. The State Bureau of Technical Supervision approved 1989-05-06 1
199001-01 implementation
Military public grade MT
Weight public value
Nominal weight, kg
>0, 4~1
>10～40
40~100
≥100～400
400~~1000
≥ 10004000
4000～10000
>1000040000
GB/T 11351-89
Table 1 Weight tolerance values ​​of castings
Note: The weight tolerance values ​​in the table are the sum of the upper and lower deviations, that is, half is the upper deviation and half is the lower deviation. 4 Marking method
4.1 When the upper and lower deviations of the weight tolerance are the same, the marking is: GB 11351—89 MT 10 grade
4.2 When the upper and lower deviations of the weight tolerance are different, it is marked as: GB11351--89MT10/8\ grade
Note: 1) The number above the slash is the upper deviation grade of the weight tolerance, and the number below the slash is the lower deviation grade of the weight tolerance. 5 Inspection and evaluation
5.1 The nominal weight of the casting and the weight of the casting to be inspected should be weighed with measuring instruments of the same precision grade. 10
5.2 If the actual weight of the casting to be inspected is less than or equal to the nominal weight and the weight tolerance, When the weight tolerance of the casting is the sum of the upper deviation or the lower deviation, the weight tolerance of the casting is qualified.
5.3 When the weight tolerance of the casting is used as the basis for acceptance, it should be indicated in the drawing or technical document. Process method
Sand mold hand
Sand mold machine
Molding and shell
Metal mold
Low-melt casting
Pressure casting
Investment casting
Molding material
X. Condensed sand
Self-hardening sand
Additional instructions:
GB/T 11351—89
Table 2 Weight tolerance grade of castings for batch and mass production Weight tolerance grade MT
Gray cast iron
12～14
Spheroidal graphite cast iron [Mallet cast iron
11～13
8～10
11～13
Copper alloy
10～12
Zinc alloy
Light alloy
Weight tolerance grade of castings for small batch and single piece production Weight tolerance grade MT
Gray cast iron
11～13
This standard is proposed by the Ministry of Machinery and Electronics Industry. This standard is under the jurisdiction of Shenyang Foundry Research Institute. This standard is drafted by Shenyang Foundry Research Institute. Ductile iron
Mallet cast iron
Nickel alloy
Copper alloy
13~～15
10～12
Cobalt-based alloy
Light metal alloy
The main drafting units of this standard are: First Automobile Manufacturing Plant, First Tractor Manufacturing Plant, Shenyang Foundry, Shenyang First Machine Tool Plant, Shenyang Heavy Machinery Plant, China Textile Machinery Plant, Tianjin Nonferrous Metal Foundry, Qishuyan Locomotive and Rolling Stock Technology Research Institute of the Ministry of Railways, and Shenyang Aircraft Manufacturing Company. The main drafters of this standard are Sun Naizhong, Song Weide, Zhao Hui, Yang Enchang, Zhu Zhongming, Peng Renshan, Ma Xun, Wang Yanming, Guo Cunhou, and Ji Shengli. From the date of implementation of this standard, the original JB2580-79 "Dimensional Tolerance and Weight Deviation of Machining Allowance of Steel Castings" and the original JB285480 "Dimensional Tolerance and Weight Deviation of Machining Allowance of Iron Castings" shall be invalidated.
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