JB/T 6702-1993 Numbering Rules for Product Drawings and Design Documents of Tractors and Agricultural Transport Vehicles JB/T6702-1993 Standard Download Decompression Password: www.bzxz.net

Ministry of Aerospace Industry of the People's Republic of China, Aviation Industry Standard
HB 6702-93
GH4169 alloy bars for WZ8 series
Published on 1993-02-22
Implementation of Ministry of Aerospace Industry of the People's Republic of China on 199308-01
Ministry of Aerospace Industry of the People's Republic of China Aviation Industry Standard WZ8 series GH4169 alloy bars
1 Subject content and scope of application
HB6702-93
This standard specifies the chemical composition, mechanical properties, test methods and inspection rules of GH4169 alloy bars. This standard applies to hot-rolled or forged GH4169 alloy bars for the manufacture of key and important rotating parts of gas turbine engines.
2 Referenced standards
The following standards constitute part of this standard within the scope specified in this standard, and the latest version should be adopted. GB222
GB2101
GB4338
GB6394
GB6395
Method for sampling samples for chemical analysis of steel and allowable deviations in chemical composition of finished products Methods for chemical analysis of steel, iron and alloys
Method for tensile testing of metals
Method for testing Brinell hardness of metals
General provisions for acceptance, packaging, marking and quality certificate of steel sections Method for tensile testing of metals at high temperatures
Method for determining the average grain size of metals
Method for tensile endurance test of metals at high temperatures
Hot-rolled high-temperature alloy bars for rotating parts
3 Dimensions and appearance
Longitudinal macrostructure acid immersion test method for high-temperature alloy bars Method for transverse macrostructure acid immersion test method for high-temperature alloy bars Longitudinal fracture test method for high-temperature alloy bars
Microstructure test method for high-temperature alloys
The dimensions of bars and their allowable deviations shall conform to the provisions of Table 1. Table 1
18～50
>50～80
>80～100
>100~80
Published by the Ministry of Aerospace Industry on February 22, 1993 Allowable DeviationWww.bzxZ.net
Implemented on August 1, 1993
HB6702-93
According to the requirements of the purchaser, bars other than those specified in Table 1 can be supplied. The size and allowable deviation shall be agreed upon by the supply and demand parties and shall be indicated in the contract.
3.2 The usual length of the bar is 2 to 5m, but the length of the bar with a diameter greater than 50mm is 1 to 4m. A small amount of bars greater than 0.6m are allowed to be delivered.
3.3 The out-of-roundness of the bar shall not be greater than 70% of the diameter tolerance. 3.4 The curvature of the bar shall not be greater than 6mm per meter. 4 Technical requirements
The chemical composition of the alloy shall comply with the provisions of Table 2. Table 2
0.0150.015
Note: Without the permission of the purchaser, no elements other than those in the composition table shall be added. Cu
4.2 The alloy is produced by vacuum induction smelting plus vacuum consumable double process; under the premise of ensuring the alloy structure and performance, it is allowed to use less than or equal to 40% of the return material; when the supplier's production process has major changes, the purchaser's consent must be obtained in advance; if necessary, both the supplier and the purchaser can view the other party's manufacturing production process and the various tests required by this standard, but both parties shall keep it confidential. 4.3 Before the ingot is processed, it must be homogenized, and the processing temperature after homogenization should not exceed 1125℃. 4.4 Delivery status: Hot-rolled or forged bars that have not been heat-treated must be delivered after turning or polishing. The specific provisions shall be stated in the contract.
4.5 Mechanical properties
4.5.1 The room temperature and high temperature mechanical properties of the bars shall be determined by heat-treated specimens and shall comply with the provisions of Tables 3 and 4. The heat treatment specification is 950~980℃×1h, air cooling +720±5℃×8h, furnace cooling at 50℃/h to 620±5℃×8h, air cooling.
4.5.1.1 The tensile properties shall comply with the provisions of Table 3. 2
Test temperature
0p,N/mm2
HB6702-93
00.2,N/mm2
% notch/% smooth ≥1.3
Note: Room temperature smooth and notched tensile specimens are cut from adjacent parts and tested separately. 4.5.1.2 High temperature endurance properties shall comply with the provisions of Table 4. Table 4
Test specimen shape
Test temperature
Fracture time, h
Elongation 85, %
Note: ①650℃ combined endurance can be replaced by smooth and notched specimens cut from adjacent parts, as long as the load surface of the working part of the specimen and the notched specimen are consistent with the combined specimen; the fracture time of the notched specimen should be greater than the fracture time of the smooth specimen. ②When the test time reaches 25h, load with an increment of 34.5N/mm every 10h until it breaks. 4.6 Macrostructure
4.6.1 Transverse macrostructure
4.6.1.1 Cut the specimens from the bars equivalent to the head and tail of each furnace ingot. When the macrostructure is inspected on the transverse acid leaching test piece without standard heat treatment, there shall be no visible shrinkage marks, cavities, cracks, pinholes, slag inclusions, folds, white spots, black spots and other defects.
4.6.1.2 When it is necessary to strengthen the inspection to find "white spot" type defects, the test piece shall be inspected immediately after standard heat treatment and corrosion, before cleaning and drying. If there are "white spots" (see Figure 2) or "black spots", the whole furnace shall be scrapped. When the diameter of the bar is greater than 100mm, the horizontal low magnification shall be inspected on the 90mmX90mm melting inspection sample. Sample etchant:
500ml concentration 36%~38%
35ml concentration 95%~98%
4.6.2 Longitudinal low magnification: For bars with a diameter less than or equal to 32mm, cut the sample from the bar equivalent to the head and tail of each furnace number of ingots, and after standard heat treatment, prepare the sample and inspect the severity of the longitudinal low magnification organization according to GB. 187.1, and take low magnification organization photos at a ratio of 1:1, accumulate data, and do not use it as the basis for acceptance for the time being. After accumulating enough data, the two parties will agree on the acceptance standard pictures.
4.6.3 Longitudinal fracture: Cut the sample from the bar equivalent to the head and tail of each furnace ingot. When checking the longitudinal fracture structure after standard heat treatment, no defects such as delamination, shrinkage, slag inclusion, cracks, etc. are allowed. 4.7 High-power structure: Cut the longitudinal sample from the core and middle of the radius of the bar equivalent to the head and tail of each furnace ingot. When necessary, take samples at low-power and fracture inspection suspicious parts. 4.7.1 Carbide: After mechanical polishing, the sample is magnified 50 times on the uncorroded surface and evaluated according to Figures 1 to 4 of Attached Figure 1. The general distribution of carbides does not exceed Figures 1 and 2. The distribution of carbides in up to 3 fields per square centimeter of the sample does not exceed Figure 3, but the remaining fields do not exceed Figure 1. 4.7.2 Laves phase: After mechanical polishing and corrosion, the sample is inspected. If Laves phase appears, the entire furnace will be scrapped. The etchant is made by mixing the following two solutions in equal amounts and diluting them to 50%. Solution 1: HNO3
Solution 2: HCl
4.7.3 Grain size: After the sample is subjected to standard heat treatment, it is evaluated according to GB6394. For bars with a diameter less than or equal to 85mm, the average grain size level is greater than or equal to 5, and individual large grains are allowed to be up to level 3; for bars with a diameter greater than 85mm, the average grain size level is greater than or equal to 4, and individual large grains are allowed to be up to level 2. 4.7.4 NisNb phase: After the sample is subjected to standard heat treatment, polishing and etching, it is evaluated according to Figures 1 to 12 of Attached Figure 3. Figures 1 to 4 are qualified organizations: Figure 58 is a limit organization, which is qualified if it does not exceed 30% of the inspected surface; Figures 9 to 12 are unqualified organizations.
The sample is electrolytically corroded in the following solution with a voltage of 3 to 5V: HCI
CH.OH100ml
4.8 Surface quality
4.8.1 There shall be no cracks, folds, scars or slag inclusions on the surface of the bars for heating processing; local defects on the surface of the bars shall be removed by inclined grinding, and the allowable removal depth shall not be greater than the negative tolerance of the delivery size. 4.8.2 Local defects are allowed on the surface of the bars for cold processing, and their depth shall not be greater than half of the dimensional tolerance, calculated from the nominal size.
4.9 The bars shall be ultrasonically inspected one by one and delivered after passing the inspection. When the amplitude of the defect on the bar is greater than or equal to the amplitude of the flat-bottom hole diameter listed in Table 5, the defective part shall be scrapped. Table 5
Material diameter
>50~180
Flat bottom hole diameter
5Test method
HB6702-93
5.1 The dimension measurement method, shape measurement method, surface quality inspection method and chemical analysis method shall comply with Articles 3.1 to 3.4 of GB. 176.
5.2 Low-power, high-power and mechanical property test methods The number, location and test method of each batch of low-power, high-power and mechanical properties samples shall comply with the provisions of Table 6. Table 6
Test items
Transverse macro
Longitudinal macro
Longitudinal fracture
Macrostructure
Grain size
High temperature endurance
High temperature tensile
Room temperature tensile
Brinell hardness
Composition sampling
Chemical analysis
Sampling location
Equivalent to one at the head and tail of the steel ingot
Equivalent to the head and tail of the steel ingot
Note: ①When the diameter of the bar is less than or equal to 32mm, the center line of the mechanical properties sample is consistent with the center line of the bar; ②When the diameter of the bar is greater than 32mm, the center line of the mechanical properties sample is at 1/2 radius of the bar. 5.3 When the purchaser retests, other commonly used methods can be used for high temperature endurance test. 6 Inspection rules
Test methods
GB6395
GB4338
6.1 The acceptance, batching, re-inspection, quality objection and arbitration test of bars shall be in accordance with Articles 4.1 to 4.5 of GB. 176. 6.2 When the demander finds metallurgical defects on finished or semi-finished parts and the defects are confirmed by both parties, the supplier shall return the goods; when the demander requests, the supplier shall make up the defects; if the supply and demand parties have disputes over the nature of the defects, they may ask the unit designated by the superior department or agreed by both parties for arbitration in order to reach a final conclusion. 7 Packaging, marking and quality certificate
Packaging, marking and quality certificate shall be in accordance with Articles 5.1 to 5.3 of GB. 176. For bars equivalent to the head of the ingot, there shall be obvious symbols and marks. For bars with a diameter greater than 30mm, the serial number shall be marked and indicated in the quality certificate. Figure 1
Carbide distribution
HB 6702-93
HB6702-93
HB6702-93
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Figure 2
White spots
HB6702-93
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