JB/T 4385.2-1999 This standard is a revision of JB 4386-87 "Complexity Classification and Conversion Factor of Hammer Free Forgings". The technical content has been adjusted during the revision. This standard is part of the JB/T 4385 "Hammer Free Forgings" series of standards. This series of standards includes the following two parts: JB/T 4385.1-1999 General technical conditions for hammer free forgings JB/T 4385.2-1999 Complexity classification and conversion coefficient of hammer free forgings This standard is applicable to hammer free forgings (or partially adopted General-purpose steel forgings produced by tire die forging) method. This standard can be used as a basis for calculating standard forging output, formulating labor quotas and energy consumption, and can also be used as a reference for formulating trade prices. This standard was first published on the year, month and day. JB/T 4385.2-1999 Complexity classification and conversion coefficient of hammer free forgings JB/T4385.2-1999 Standard download and decompression password: www.bzxz.net

JB/T4385.2—1999
Previous
Preface
This standard is a revision of JB4286--86 "Complexity Classification and Conversion Factor of Hammer Free Forgings". Compared with JB4286-86, the main technical content of this standard has changed as follows: 1) According to relevant regulations, a preface has been added. 2) Adjusted the complexity classification of some forgings in Table 1. For example: downgrade the 8th, 13th, 16th and 19th forgings of the original Category 1 to Category 1; upgrade the 10th forgings of the original NV category to a sub-category; upgrade the 12th forgings of the original category V to Category IV; upgrade the original NV forgings to Category IV; Category 4 and 5 forgings are reduced to Category X. 3) The nominal conversion coefficient of Class 1 forgings in the original Table 2 is adjusted from 5.5 to 5.0. 4) The complexity of the 195 diesel engine crankshaft forgings in the example is reduced from the original Class 1. to Class I, and its conversion coefficient is also reduced accordingly. 5) The forging steel grades in Table 5 are replaced by new grades Q235-A and Q235-B for the old grades A3 and B3, and 8Cr13 is cancelled. This standard replaces JB4286-86 from the date of implementation. This standard is proposed and administered by the National Forging Standardization Technical Committee. This standard was drafted by: First Design Research Institute of the Ministry of Machinery Industry. Who is the main drafter of this standard: Lian Wu, Li Baoqian. 283
Machinery Industry Standard of the People's Republic of China
Classification for complexity & equivalent coefficient of open die forgings on hammer range
7
JB/T4385.2---1999
replaces JB1286·86
This standard is applicable to general-purpose steel forgings produced by hammer free forging (or partial die forging). This standard can be used as a basis for statistics on the standard output of forgings, setting labor quotas and energy consumption, and can also be used as a reference for setting trade prices. 2. Classification of complexity of free forgings on hammer
This standard is classified according to the complexity of the shape of forgings. It is divided into nine categories, see Table 1. Table 1 Classification table of complexity of free forgings on hammer Category
eo
m
National Machinery Industry Bureau approved 284 on June 24, 1999
Forging shape example||tt ||Lor -kro
Sel
Jeneai
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010
o
DrDD
2000-01 -01Implementation
14
t
JB/T 4385.2—1999
Table 1 (continued)
Forging shape example
15
Q10t
rack expansion
16
28
17
18
285
Category
286
cubic
JB/T 4385.2--1999
Table 1 (continued)
HA>0.25
S≤ 20mm
Punch reaming
Category
1
B/H3
2
God hole
2| |tt||Sphere
2
Note: The weight of the symbol Q in the table is H-
3 conversion coefficient
Height, A
JB /T 4385.2—1999
Table 1 (End)
Forging shape
Example
3
L/D≤20
4
LIA<15
5
L/D≥20
The side length of the square, thickness, L--length, D-outer diameter, B. height . BH3
LiA≥15
The nominal conversion coefficient of each type of forgings is as specified in Table 2. This standard is based on training forgings (nominal conversion coefficient Zm - 1), and is revised according to the following conditions:
a) According to the tonnage of the equipment used for forging production, it is revised according to Table 3; b) According to the batch size of forgings, Revise according to Table 4; c) According to the steel number of the forging, revise according to Table 5; d) For forging damage of hot die forging pre-forging, after being classified according to its shape, it will be reduced to one category for calculation (for example, Category I is reduced to Category II , and so on), but those belonging to category X are still calculated according to the district category.
Table 2 Nominal conversion coefficient (Zm) table
Forging category
Nominal conversion coefficient Zm
Forging hammer dropped part weight 1
Correction coefficient Xa| |tt||Forging batch (pieces)
Correction coefficient ||3.00
N
2.30
1.70
Table 3 Equipment tonnage correction coefficient (X.) Table
0.40~0.56
1.00
Table 4
25
1.00
0. 75~1. 00
0. 90
M||tt| |1.35
1.50~2. 00
0.82
Forging batch correction coefficient (X.) table
25~~50
0.96||tt ||1. 00
3.00
0.78
0.85
51
0.90
0.65
5. 00| |tt||0.75
287
Type of steel
and steel number
Examplebzxz.net
Correction coefficient
X||tt| |Note
Type
Steel number example
Steel ingot
Steel bad rolled products
JB/T 4385.2—-1999
Table 5
Forging steel number correction coefficient (X) table
Ordinary carbon steel
High-quality carbon steel
Alloy structural steel
Q235-A|| tt||Q235-B
15, 25
35, 45
20Mn
50Mn
20Cr
40Cr||tt| |15CrMo
20CrMo
35CrMo
12CrMoV
20CrMnTi
1.2
1.0
Carbon Tool Steel||tt ||Spring steel
Alloy structural steel
T7, T8
4SCrNi
60Si2
60CrMn
12CrNi3A
60i2Mm
300r2MoV
1.5
1.2
Ball bearing steel
Alloy tool steel
Carbon tool steel
GCr15| |tt||T9~T13
5CrNiMo
5CrMnMo
2.0
1. 4
The steel numbers listed in the table are only exemplary. When using other steel grades, it can be determined according to the original measurement in the table. Stainless steel
Heat-resistant steel
Alloy tool steel
1Cr13-- 4Cr13
3Cr2W8
5CrW2si
CrwMn
CriMov
Cr12WMoNbVB
Cr12Ni2WMoV
Cr17Ni2
1Cr18Ni9Ti
4Cr5W2MoV
3.0
1.8
2 pairs of high speed Steel, if there are special process requirements (if repeated roughening and drawing are required), the correction coefficient shall be specifically determined by both the supply and demand parties. The conversion coefficient of the forging can be calculated by formula (1): Z - ZmX.X,X.||tt| |In the formula: 2-
Z.
Conversion coefficient;
Nominal conversion coefficient (see Table 2);
Xa--Equipment tonnage correction coefficient (see Table 3); -Forging batch correction coefficient (see Table 4); X. —Forging steel number correction coefficient (see Table 5). Shangsu Steel
Stainless steel, heat-resistant steel
Alloy tool steel
W18CrAV
W9Cr4V2
Cr12
Gr12Ms
Cr12MoV
Cr15Ni36W3Ti
3. c
3.(
Example: 195 diesel engine crankshaft forgings, as shown in Figure 1, material: 45 high-quality carbon steel rolled Material; forging weight: 27kg; forging batch: 5 pieces; equipment used: 1t free forging hammer. Calculate its conversion coefficient Figure 1195 diesel engine crankshaft forging schematic calculation method is as follows:
First, according to the shape of the crankshaft forging, you can The first physical category found in Table 1 is similar to it, so the forging belongs to Category II forgings. According to the category of the forging and other known conditions, the definition can be found in Table 2, Table 3, Table 4, and Table 5 respectively: 2m==4.00, Quantity) can be converted into 3.60 times of standard forgings 288
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