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
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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. 269 Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.