This standard specifies the technical requirements for ordering, manufacturing and acceptance of carbon tool steel for large forgings. This standard applies to carbon tool steels for general purposes of large forgings. JB/T 6394-1992 Carbon tool steel for large forgings JB/T6394-1992 Standard download and decompression password: www.bzxz.net

Machinery Industry Standard of the People's Republic of China
Carbon Tool Steel for Large Forgings
1 Subject Content and Scope of Application
This standard specifies the technical requirements for ordering, manufacturing and acceptance of carbon tool steel for large forgings This standard applies to carbon cable tool steels for general purposes of large forgings. 2 Reference standards
GB222
Sample sampling methods for chemical analysis of steel and chemical tolerances of finished products GB223
Methods for chemical analysis of steel and alloys
GB224||tt ||GB226
GB 227
G230
GB 231
Method for determination of decarburized layer depth of steel
Low magnification structure and defects of steel acid etching Test method Carbon tool steel plate permeability test method
Metal Rockwell hardness test method
Metal Brinell hardness test method
Steel fracture inspection method
GB 1814| | tt | Indicate the name, category, steel type, delivery status and supply quantity of the forgings. 3.2 The purchaser shall provide the ordering drawings and related finishing drawings jointly approved by both parties. 3.3 When the purchaser has appendix A (supplementary parts) or other requirements for supplementary test items, it should be agreed upon by both parties. 4 Manufacturing
4.1 Smelting
Carbon tool steel should be smelted using electric furnace or other methods. 4.2 Forging
4.2.1 The head and tail of the steel ingot should be sufficiently cut off to ensure that the forgings have no shrinkage holes and severe segregation JB/T 6394.92bzxZ.net
4.2.2 The forgings should be Forging and forming on forging equipment with sufficient capacity to ensure that the interior of the forging is fully forged. 4.3 Heat treatment
The forging should be annealed or heat treated according to the delivery status of the forging stipulated in the order contract. 5 Technical requirements
5.1 Steel grade and chemical composition
5.1.1 The steel grade and chemical composition (smelting analysis) should comply with the provisions of Table 1. Use graded high-quality steel (add A after the grade), the sulfur content is not more than 0.020%, and the phosphorus content is not more than 0.030%. Approved by the Ministry of Mechanical and Electronic Industry of the People's Republic of China on 1992-07-14 266
Implemented on 1993-07-01
Brand
No.
T7
T8
T8Mn
T9
T10
T11|| tt||T12
T13
C
0. 65 ~~ 0. 74
0.75~0.84
0.80~0.90
0.85-0.94
0.95-1.04
1.05-1.14
1. 15~1. 24
1. 25~-1.35
Pei 1| |tt||JB/T6394
—92
Steel grade and chemical composition
Chemical
Si
.0.35
0.35| |tt||0.33
.0.35
0.35
50.35
50.35
0.35
学
成|| tt||Mn
o.40
0.10
0.400.60
0.40
0.40
0.40
0.40 | |tt | . 5.1.2 The allowable deviation of the chemical composition of forgings shall comply with the provisions of JB/ZQ4000.7. 5.2 Hardness
5.2.1
5.2.2
The hardness of forgings should comply with the requirements in Table 2.
When the purchaser requires the forgings to be quenched and tempered, the hardness requirements of the forgings can be determined separately. Table 2
Hardness
Annealing state
Brand
T7
No.
T8
T8Mn
T9
T10
T11
T12
T13
Surface defects and removal
5.3
Collision value|| tt||HB
187
187
187
192
197
207
207||tt| |217
Jihuo temperature
C
800-820
780~800
780~800
760-780|| tt||760~~780
760~780
760~780
760--780
ze
annihilation
0.035
0.035
0.035
0.085
0.035
0.035
0.035
0.035
like|| tt||coolant
water
water
water
water
water
water
water||tt ||Water
State
No more people
0.080
0.030
9.030
0.030
0.030||tt ||0.030
0.030
0.030
Trial hardness value
HRC
62
62
2|| tt||62
62
62

62
The surface of forgings shall not have cracks, folds, scars and inclusions visible to the naked eye. When forgings If there are peripheral defects on the surface, they can be removed. The removal depth shall not be greater than 75% of the machining allowance and shall be smoothly transitioned to the surrounding surface. 5.4 Shape and size
The shape and size of the forgings should comply with the requirements of the forging ordering drawings. Test methods and inspection rules
6
6.1
Forging inspection shall be carried out by the supplier.
6.2 The number of specimens, sampling locations and test methods used for random inspection of forgings of the same furnace, same size and same heat treatment batch shall comply with the provisions of Table 3.
267
Test items
Chemical composition
Fire hardness
Sample quenching hardness
JB/T6394—92||tt ||Table 3 Sampling requirements and test methods
Test methods
GB223
GB231
GB230
Note: The attached sample refers to forgings per heat batch Individually forged specimens. Acceptance retest and Yingxin heat treatment
Sampling requirements
GB 222
Forging surface
Attached sample
7.1
When the chemical composition of the forging , hardness and appearance dimensions shall be inspected and accepted if they meet the requirements of the order contract. Sampling quantity
2
Art
When the test results do not meet the requirements, retesting and taking double samples are allowed. If the retest fails, it can be reheated and retested. The number of reheat treatments shall not exceed 3 times, and the number of temperings is not limited. Certificate of Conformity
8
When the forgings leave the factory, the supplier shall provide the demander with a certificate of conformity with the test results specified in the order contract. 9 Printing and packaging
9.1 Each forging should be printed with the supplier's factory mark, contract number, drawing number, and melting furnace number at the corresponding steel ingot nozzle end. 9.2 The surface of machined forgings must be protected against rust to avoid damage during packaging and transportation. 268
A1 low inertia and fracture
JB/T6394—92
Appendix A
Supplementary test items
(Supplement)
A1.1 There should be no shrinkage cavity residues, inclusions, cracks, bubbles and white spots visible to the naked eye on the acid-soaked low-magnification test pieces of forgings. The test method is in accordance with GB226.
A1.2 Central porosity and segregation shall be evaluated according to the third level diagram. The qualified level shall be agreed upon by both parties. The test method shall be in accordance with GB226. A1.3 The fracture of forgings shall not have visible delamination, cracks, inclusions, shrinkage residues, white spots and graphite carbon. The test method shall be in accordance with GB1814.
A2 Pearlite structure
When the pearlite structure is required to be inspected for forgings in the annealed state, the qualified level shall be agreed upon by both parties and evaluated according to the first level diagram. A3
Network carbide
Network carbide inspection of forgings shall be evaluated according to the second level diagram. The qualified level shall be agreed upon by both parties. The test method shall be carried out in accordance with the provisions of YB28 standard.
A4 Total depth inspection of decarburized layer
When the purchaser requires the total depth of decarburized layer to be measured, the total depth of decarburization on one side shall be agreed upon by both parties. The test method shall be in accordance with (B224. A5
5 Hardenability
The hardenability level or hardening depth shall be specified in the contract, and the hardenability test method shall be carried out in accordance with GB22? Additional remarks:
This standard is proposed and managed by the Deyang Large Castings and Forgings Research Institute of the Ministry of Machinery and Electronics Industry. This standard was drafted by the Deyang Large Castings and Forgings Research Institute of the Ministry of Machinery and Electronics Industry. The main drafter of this standard is Pan Fengqin.
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