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This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 12362-2003 “Steel Die Forgings-Tolerance and machining allowances”. Compared with GB/T 12362-2003, except for editorial changes, the main changes are as follows:
- Replace the “Machine Machining Margin and Its Usage Principle” in the scope with “Machine Machining Remaining Level and Technical Content”, and change the “Structured Steel Forgings” to “Structural Steel Die Forgings” and replace “250kg” with “500kg”. (See Chapter 1, Chapter 1 of the 2003 Edition.)
- Remove "forgings that required additional manufacturing processes to be achieved" and "flat forged parts used only at ordinary level" (see 2.1 in 2003)
In the special case a) of 3.1.2, “In selecting tolerances, the mass of the forging is considered only the mass of the cylindrical part of diameter d and thickness t; if this special rule selects a tolerance less than that of 3.1.2 Tolerances selected by the rules are selected according to the general rules of 3.1.2” is added (see 3.1.2).
In the special case b) of 3.1.2, the “Where selecting the dimensional tolerances of the relevant features, the quality of the forgings only considers the mass of the cylinder with a diameter of d1 and a thickness of t1; if the tolerances chosen for this special rule are less than .2 Tolerances for general rules are based on the tolerances selected in 3.1.2 General rules (see 3.1.2) is added;
Remove “Where using coal-fired or secondary-fired heating, consider increasing the tolerance or margin appropriately, the value of which shall be determined through negotiation between the supply and demand sides” (see 3.1.6 of the 2003 edition).
Change "error tolerance" to "error" (see 3.2.4, 2003 version 3.2.4)
Change "deep tolerance" to "depth" (see 3.2.14, 2003 version 3.2.14)
The quality ranges in Table 1, Table 2, Table 3, Table 4, and Table 16 are revised and the query lines are added (see Table 1, Table 2, Table 3, Table 4, Table 16, Table 1, Table 2 of 2003 Edition), Table 3, Table 4, Table 16)
The aperture range in Table 15 is modified and the query line was added (see Table 15, Table 15 of the 2003 Edition).
This standard was proposed and is under the jurisdiction of the National Forging Standardization Technical Committee (SAC/TC74).
The previous versions of the standards replaced by this standard are:
- GB/T 12362-1990, GB/T 12362-2003.
Steel Die Forgings-Tolerance and Machining Allowance
1 Scope
This standard specifies the steel die forgings (hereinafter referred to as "forgings") tolerances and machining allowance levels and technical content.
This standard applies to die forging hammers, hot die forging presses, screw presses, flat forging machines and other forging equipment production of structural steel die forgings.
Other steel forgings can also be used as reference. This standard applies to forgings with a mass less than or equal to 500kg and a length (maximum size) less than or equal to 2500mm.
2 Level of Tolerances and Machining Allowances
2.1 The tolerance is divided into two levels: ordinary level and precision level.
Ordinary tolerances apply to forgings that meet the technical requirements of general die forging processes.
Precision tolerances apply to forgings with higher technical requirements and can be used for the full size of a forging and for local dimensions.
2.2 The Machining Allowance is Only One Level.
3 Technical Content
3.1 The main factors to determine forging tolerance and machining allowance
3.1.1 Forging Mass mf
Forging quality are estimated according to the following procedure:
The basic dimensions of the part drawing → Estimate the machining allowance → Draw the forging drawing → Estimate the forging quality, and determine the tolerance and machining allowance according to this quality check table.
3.1.2 Forging Shape Complex Factor S
The forging complex shape factor is the ratio of the forging mass mf to the corresponding forging external shell mass mN, see Equation (1):
S=mf/mN (1)
The forging profile containment mass mN is the calculated mass of the cylinder or cuboid containing the largest profile of the forging as the entity, and is calculated according to formula (2) or formula (3):
a) Round forgings (Figure 1)
mN=1/4·π·d2·h·ρ (2)
Where:
ρ——Steel density(7.85g/cm3)
Figure 1 Round Forgings?
b) Non-circular forgings (Figure 2)
mN=l·b·h·ρ (3)
Figure 2 Non-circular Forgings
According to the size of S value, forging complex shape factor is divided into 4 levels:
S1 level (simple): 0.63
Foreword i
1 Scope
2 Level of Tolerances and Machining Allowances
3 Technical Content
Annex A (Informative) Forging Tolerance Application Example
ICS 77.140.85
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中華人民共和國國家標準
GB/T 12362-2016
代替GB/T 12362-2003
鋼質模鍛件
公差及機械加工余量
Steel die forgings-Tolerance and machining allowance
2016-12-13發布 2017-07-01實施
中華人民共和國國家質量監督檢驗檢疫總局
中國國家標準化管理委員會
發布
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前言
本標準按照GB/T 1.1-2009給出的規則起草。
本標準代替GB/T 12362-2003《鋼質模鍛件 公差及機械加工余量》，與GB/T 12362-2003相比，除編輯性修改外，主要變化如下：
——將范圍中“機械加工余量及其使用原則”改為“機械加工余量等級和技術內容”，將“結構鋼鍛件”改為“結構鋼模鍛件”，將“250kg”改為“500kg”（見第1章，2003年版的第1章）；
——刪除了“但需要采取附加制造工藝才能達到的鍛件”和“平鍛件只采用普通級”（見2003年版的2.1）；
——在3.1.2特殊情況a）中，增加了“在選取公差時，鍛件質量只考慮直徑為d、厚度為t的圓柱體部分的質量；如果此特殊規則選取的公差小于按3.1.2-般規則選取的公差，則按3.1.2一般規則選取公差”（見3.1.2）；
——在3.1.2特殊情況b）中，增加了“在選取相關特征的尺寸公差時，鍛件質量只考慮直徑為d1、厚度為t1的圓柱體部分的質量；如果此特殊規則選取的公差小于按3.1.2一般規則選取的公差，則以3.1.2一般規則選取的公差為準”（見3.1.2）；
——刪除了“采用煤加熱或二火加熱時，可考慮適當增大公差或余量，其數值由供需雙方協商確定”（見2003年版的3.1.6）；
——將“錯差公差”改為“錯差”（見3.2.4，2003年版的3.2.4）；
——將“深度公差”改為“深度”（見3.2.14，2003年版的3.2.14）；
——修改了表1、表2、表3、表4、表16中的質量范圍并增加查詢行（見表1、表2、表3、表4、表16，2003年版的表1、表2、表3、表4、表16）；
——修改了表15中的孔徑范圍并增加查詢行（見表15，2003年版的表15）。
本標準由全國鍛壓標準化技術委員會（SAC/TC74）提出并歸口。
本標準主要起草單位：東風鍛造有限公司、北京機電研究所。
本標準主要起草人：吳玉堅、吳聽松、魏巍、金紅、趙業勤、陳文敬、程琛文。
本標準所代替標準的歷次版本發布情況為：
——GB/T 12362-1990、GB/T 12362-2003。
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鋼質模鍛件公差及機械加工余量
1范圍
本標準規定了鋼質模鍛件（以下簡稱“鍛件”）的公差及機械加工余量等級和技術內容。
本標準適用于模鍛錘、熱模鍛壓力機、螺旋壓力機、平鍛機等鍛壓設備生產的結構鋼模鍛件。其他鋼種的鍛件亦可參照使用。本標準適用于質量小于或等于500kg，長度（最大尺寸）小于或等于2500mm的鍛件。
2公差及機械加工余量等級
2.1本標準中公差分為兩級：普通級和精密級。
普通級公差適用于一般模鍛工藝能夠達到技術要求的鍛件。
精密級公差適用于有較高技術要求的鍛件。精密級公差可用于某一鍛件的全部尺寸，也可用于局部尺寸。
2.2機械加工余量只采用一級。
3技術內容
3.1確定鍛件公差和機械加工余量的主要因素
3.1.1鍛件質量mf
鍛件質量的估算按下列程序進行：
零件圖基本尺寸→估計機械加工余量→繪制鍛件圖→估算鍛件質量，并按此質量查表確定公差和機械加工余量。
3.1.2鍛件形狀復雜系數S
鍛件形狀復雜系數是鍛件質量mf與相應的鍛件外廓包容體質量mN之比，見式（1）：
S=mf/mN （1）
鍛件外廓包容體質量mN為以包容鍛件最大輪廓的圓柱體或長方體作為實體的計算質量，按式（2）或式（3）計算：
a）圓形鍛件（圖1）
mN=1/4·π·d2·h·ρ （2）
式中：
ρ——鋼材密度（7.85g/cm3）。
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外廓包容體
外廓包容體
圖1圓形鍛件
b）非圓形鍛件（圖2）
mN=l·b·h·ρ （3）
外廓包容體
外廓包容體
圖2非圓形鍛件
根據S值的大小，鍛件形狀復雜系數分為4級：
S1級（簡單）：0.63
GB/T 12362-2016 引用如下標準： |
GB/T 12362-2016被如下標準引用：
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