JB/T 9178.2-1999 JB/T 9178.2-1999 Complexity classification and conversion coefficient of free forgings on hydraulic press JB/T9178.2-1999 Standard download decompression password: www.bzxz.net

ICS25.020
Machinery Industry Standard of the People's Republic of China
JB/T9178.2—1999
Classification of complexity and equivalentcofficient of open die forgings on hydraulic press
Issued on 1999-06-24
National Bureau of Machinery Industry
Implemented on 2000-01-01
JB/T9178.2-1999
This standard is a revision of ZBJ32002-88 "Classification of complexity and equivalentcofficient of open die forgings on hydraulic press". Compared with ZBJ32002-88, the main technical content of this standard has been changed as follows: 1) Adjust the original complexity classification and equivalentcofficient 2) Adjust the material steel type and examples.
3) Add the correction factor of over-length of the optical axis, the correction factor of repeated upsetting and drawing, and the correction factor of internal quality. This standard replaces ZBJ32002-88 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Forging Standardization. The drafting units of this standard are Shanghai Electric (Group) Corporation and Shanghai Zhengsheng Forging Co., Ltd. The main drafters of this standard are Dong Zhusheng and Pan Baimao. 1 Scope
Machinery Industry Standard of the People's Republic of China
Open Die Forgings on Hydraulic Press
Classification of complexity and equivalent cofficient of open die forgings on hydraulic press This standard specifies the classification of complexity, equivalent coefficient and application examples of open die forgings on hydraulic press. JB/T9178.2-1999
Replaces ZBJ32002-88
This standard applies to steel forgings produced by open forging method on hydraulic press. This standard can be used as a basis for statistical forging standard output, energy consumption and labor quota formulation, and can be used as a reference for formulating trade prices. 2 Classification of complexity of free forgingsbzxz.net
This standard classifies forgings according to the complexity of the shape of the forgings, and is divided into five categories (see Table 1). Table 1 Classification of complexity of forgings
Examples of forging shapes approved by the State Machinery Industry Bureau on June 24, 1999
Implementation on January 1, 2000
JB/T9178.21999
Table 1 (continued)
Examples of forging shapes
(See note for the difference between large and small diameters)
(See note for the difference between large and small diameters)
(See note for the difference between large and small diameters)
JB/T9178.2-1999
Table 1 (continued)|| tt||Example of forging shape
(Difference between large and small diameters see note)
B/H≥3
(Difference between large and small diameters see note)
JB/T9178.2-1999
Table 1 (end)
Example of forging shape
Note: Based on the large diameter, there is a step where the difference between large and small diameters is ≥20%3Conversion coefficient
3.1 This standard specifies the nominal conversion coefficient for each type of forging based on Class IV forgings (nominal conversion coefficient Z=1) (see Table 2). Table 2 Nominal conversion coefficient Zm
Forging category
Nominal conversion coefficient Z
According to the overlength of the optical axis type (Class V, Types 1 and 2 in Table 1), it shall be corrected according to Table 3. Table 3 Correction coefficient for over-length of optical axis X
Length-to-diameter ratio L/D
Correction coefficient X
According to the forging damage, it needs to be reheated and repeatedly upsetting, and it is corrected according to Table 4. Table 4 Correction coefficient for repeated upsetting Xa
Additional times of upsetting
Correction coefficient X
One upsetting
According to the internal quality of the forging,
Test items need to be done, and it is corrected according to Table 5.
Table 5 Correction coefficient for internal quality Xv
Item name
Correction coefficient Xy
1 Xy=1+≥Xvip
Mechanical properties
Without sulfur imprint
Including sulfur imprint
Non-metallic inclusions
2 The internal quality correction coefficient of special forgings (such as rotors, impellers, retaining rings, etc.) shall be determined as appropriate. 4
Every increase of 15
Secondary upsetting
Ultrasonic flaw detection
Grain size
Magnetic flaw detection
3.5According to the material of forgings, modify according to Table 6. JB/T9178.2-1999
Table 6 Forging Material Correction Factor X
Ordinary Carbon Steel
High Quality Carbon Steel
Alloy Structural Steel
20，25，35
45,5516Mn
50Mn，20Cr
35CrMo
12CrMo
20MnMo
50CrMo
Carbon Tool Steel
Spring Steel
(Alloy Structural Steel)
45CrNi
60CrMn
12CrNi3A
60Si2Mn
30Cr2MoV
34CrNi3MoV
26Cr2Ni4MoV
34CrNiiMo
The conversion coefficient of forgings can be calculated according to formula (1): 3.6
Wherein: Z
Conversion coefficient of forgings;
Nominal conversion coefficient (see Table 2);
Correction coefficient for overlength of shafts (see Table 3);
XaRepeated upsetting and drawing correction coefficient (see Table 4): XInternal quality correction coefficient (see Table 5);
4Example
Forging material correction coefficient (see Table 6).
Ball bearing steel
Alloy tool steel
(Carbon tool steel)
T9~T13
5CrNiMo
5CrMnMo
5CrW2Si
40MnCrSi2
Z-ZmXXaX,X
Stainless steel
Heat-resistant steel
(Alloy tool steel)
1Cr13~4Cr13
3Cr2W8V
1Cr12WMoV
2Cr12NiWMoV
Cr17N i2
1Cr18Ni9Ti
9Cr2Mo
High speed steel
(stainless steel, heat-resistant
steel, alloy tool steel)
W18Cr4V
W9Cr4V2
Cr12MoV
Cr15Ni36W3Ti
50Mn18Cr4WN
40Mn18Cr3
50Mn18Cr4N
....(1)
Example: spindle forging, material 26Cr2Ni4MoV, forging weight 47.4t. Technical requirements Forging inspection items include ob,: α, S, ak, sub, HB, low magnification (including sulfur print), grain size and ultrasonic flaw detection, forging ratio requirement greater than 3. According to the shape of the forging, the second type of Class II can be found in Table 1, and Z=1.30 can be found from Table 2. According to the forging ratio and forging process requirements, a reheating upsetting is required, and X-1.3 can be found from Table 4. According to the requirements of the internal quality inspection items, Xy-1+(0.02+0.02+0.01+0.07+0.012+0.15)=1.282 can be found from Table 5. According to the forging material grade, X=1.15 can be found from Table 6. Calculate the forging conversion coefficient:
Z-ZmX.X,X-1.3X1.3X1.282×1.3-2.81, that is, the standard output of the forging converted into Class IV forgings should be 2.81 times its actual weight. 5
People's Republic of China
Mechanical Industry Standard
Free Forgings on Hydraulic Press
Complexity Classification and Conversion Coefficient
JB/T9178.21999
Published by the Mechanical Science Research Institute
Printed by the Mechanical Science Research Institute
(No. 2, Shouti South Road, Beijing
Postal Code 100044)
Word Count 12,000
Format 880×1230
Printing sheet 1/2
First edition in November 1999
First printing in November 1999
Print run 1-500
Price 5.00 yuan
99-948
Mechanical Industry Standard Service Network: 6
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