JB/T 6431-1992 Technical requirements for grey iron castings for positive displacement compressors
Some standard content:
Mechanical Industry Standard of the People's Republic of China
JB/T 6431-1992
Technical Conditions for Grey Iron Castings for Volumetric CompressorsPublished on July 20, 1992
Implementation by the Ministry of Machinery and Electronics Industry of the People's Republic of China on January 1, 1993
Mechanical Industry Standard of the People's Republic of China
Technical Conditions for Grey Iron Castings for Volumetric Compressors 1 Subject Content and Scope of Application
JB/T 6431-1992
This standard specifies the technical requirements, test methods, inspection rules and marking, packaging, transportation, storage and other requirements for grey iron castings for volumetric compressors.
This standard applies to gray iron castings (hereinafter referred to as "castings") cast in sand molds or molds with thermal conductivity equivalent to that of sand molds, with graphite in flake form.
2 Reference standards
GB6414
GB9439
GB/T 11350
GB/T11351
3 Technical requirements
Casting dimension tolerance
Gray cast iron parts
Machining allowance of castings
Weight tolerance of castings
3.1 Castings shall be manufactured in accordance with this standard and drawings and technical documents approved by the prescribed procedures. 3.2 Casting materials shall be HT150, HT200, HT250 and HT300. The mechanical properties shall comply with the provisions of GB9439 and serve as the basis for acceptance.
3.3 The chemical composition of gray cast iron is generally determined by the supplier. If the purchaser has special requirements, the supply and demand parties shall agree in the order agreement. 3 .4 The sulfur content of castings such as piston rings, cylinder blocks (without cylinder liners), cylinder liners, sealing rings and oil scraper rings shall not exceed 0.12%, and the phosphorus content shall not exceed 0.25%. Their metallographic structures shall comply with the provisions of Table 1 and serve as the basis for acceptance. Table 1
Casting name
Piston ring
Cylinder block (without cylinder
line), cylinder liners,
Seal ring, oil scraper ring
Matrix structure
Sorbitite or fine lamellar
Pearlite
Pearlite amount ≥ 95%
Fine lamellar or medium lamellar
Pearlite
Pearlite amount ≥ 95%
|Graphite distribution shape
Flake and chrysanthemum shape
Phosphorus eutectic distribution shape
Continuous network is not allowed
3.5Castings with hardness requirements should be indicated on the drawings and used as the basis for acceptance. Phosphorus eutectic-sulfonate
Composite
Blocks are allowed and they are uniform
3.6Castings such as fuselage, middle body, connecting sleeve, cylinder block, cylinder head, cylinder head, cylinder seat, cylinder liner, piston, crosshead body, valve seat and lift limiter should be aged. 3.7The dimensional tolerance of the casting geometry should comply with the drawing requirements. Its dimensional tolerance should not be greater than the CT9 grade specified in GB6414. The wall thickness and rib thickness tolerance should not be less than 0.01mm. Greater than CT10 grade specified in GB6414, the machining allowance of castings shall be selected according to CT9 grade specified in GB/T11350. Approved by the Ministry of Machinery and Electronics Industry on July 20, 1992 and implemented on January 1, 1993
JB/T6431-1992
: The weight tolerance of moving castings such as crosshead body, crosshead sliding shoe, piston and balance block shall not be greater than MT93.8
grade specified in GB/T11351, and the weight tolerance of castings shall be indicated on the drawings. 3.9 The radius of the uncast fillet of the casting shall be 1/6~1/4 of the wall thickness3.10
The misalignment of the casting shall not be greater than half of the wall thickness tolerance, and shall be scraped and ground flat. 3.11
The defects of the casting such as the molding sand, core sand, gate, eyelet, sand inclusion scar, mechanical sand adhesion and fleshiness shall be cleaned up. The machined surface of the casting is not allowed to have surface defects exceeding the machining allowance. 3.12
A single clean pore is allowed to exist on the friction surface of the cylinder block and cylinder liner, the machined surface of the piston, the slideway surface and the machined surface of the thin-walled bearing seat, but its diameter, depth and number shall not exceed the requirements of Table 2. Table 2
Cylinder block friction surface
Cylinder liner friction surface
Piston machined surface
Slideway surface
≤500www.bzxz.net
Thin-walled bearing seat machined surface
≤500
Pore diameter
Pore depth
≤1/7 wall thickness
Pore spacing
Number of pores (pieces)
The main parts of the following castings should not have cracks visible to the naked eye, Shrinkage cavities, shrinkage and sand holes are not allowed to be welded: a.
Threaded holes of flange surfaces between castings such as fuselage, middle body, coupling, cylinder block, cylinder seat, cylinder head and cylinder cover: threaded holes of cylinder valve hole flange and inlet and exhaust port flanges; friction surfaces and slide surfaces of castings such as cylinder block, cylinder liner and crosshead body: machined surfaces of valve seat and lift limiter;
piston end face, outer cylindrical surface, piston ring groove end face and bottom surface; matching surface and sealing surface of cylinder valve chamber.
Other machined surfaces of castings other than those specified in Articles 3.13 and 3.14 are not allowed to have cracks and shrinkage cavities, and other defects with a diameter greater than 10mm, a depth greater than 1/7 of the wall thickness, a spacing less than 50mm and a number exceeding 5 are not allowed to exist within every 100cm area. Casting defects visible to the naked eye are not allowed on the machined surfaces of castings such as piston rings, sealing rings and oil scrapers. 3.16
No cracks are allowed on the non-machined surface of the casting. Special requirements shall be in accordance with the drawings. Pressure castings such as cylinders and pistons shall be subjected to water pressure test after machining. 3.18
Other parts except those specified in Articles 3.13 and 3.14 may be eliminated by welding if there are defects exceeding the allowable range. 3.19
But the following provisions must be met.
3.19.1 The depth of welding should not exceed 1/2 of the wall thickness of the part where the welding is done. 3.19.2 Before welding, the defective part should be cleaned to expose the original color of the metal. After welding, it should be ensured that the casting does not produce cracks, deformation and white spots. After welding, the welding stress should be eliminated. 3.19.3 After welding the machined surface, the hardness difference between the welding part and the transition zone and the main body should not exceed 25HB. 3.19.4 Castings that are welded due to water leakage during the water pressure test should be re-tested after welding. 4 Test methods
The mechanical properties, metallographic structure inspection methods and chemical composition analysis methods of castings shall comply with the provisions of GB9439. 2
5 Inspection rules
JB/T6431-1992
Castings shall be inspected in accordance with the provisions of this standard, product drawings and technical documents. 5.14
5.2 The inspection rights and locations of castings shall comply with the provisions of GB9439. 5.3 Castings cast from the same package of molten iron shall be defined as a casting batch. 5.4 The geometric shape and size of castings, the first piece shall be inspected by line, and normal production parts shall be inspected by batch. The number and method of inspection shall be determined by the inspection department of the supplier.
5.5 The weight deviation of castings shall be inspected by batch. The number and method of inspection shall be determined by the inspection department of the supplier. 5.6 Each batch of castings shall be subjected to at least one tensile test. During the test, a tensile test specimen shall be used for the test. If the test is qualified, the casting represented by the test specimen shall be qualified. If the test is unqualified and it is not caused by the reasons listed in Article 5.7, two more test specimens can be taken from the same batch of test specimens. If both specimens are qualified, the batch of castings shall be qualified for re-test. If there is still one unqualified specimen, the batch of castings shall be unqualified. 5.7 If the tensile test result is unqualified due to one of the following reasons, the test shall be invalid and shall be retested in accordance with Article 5.6: Improper installation or improper operation of the specimen:
b. Casting defects or improper processing of the specimen: c. Casting defects on the fracture of the specimen.
5.8 At least one casting shall be sampled for each batch of castings with hardness requirements. The hardness of the same casting shall be tested at 3 points and the average value shall be taken, but the difference in hardness values at the 3 points shall not be greater than 25HB
5.9 At least one casting shall be tested for each batch of castings with metallographic structure requirements. Visible surface defects of castings should be inspected piece by piece by visual method. 5.10
Chemical composition test of castings can be sampled from the as-cast test block, or it can be replaced by a hardness test block. 5.11
6 Marking, packaging, transportation and storage
6.1 If the size allows, the supplier's manufacturing number should be cast on the non-machined surface of the casting; if the size does not allow, it should be marked by typing, painting, etc. according to the batch.
6.2 For castings that pass the inspection, the inspection department shall produce a certificate of conformity and a quality certificate (certificate card), the contents of which shall include the supplier's name:
Casting name:
Casting drawing number and material brand and technical index inspection record; c
Manufacturing date, production number.
6.3 The surface protection, packaging, transportation and storage of castings shall comply with the provisions of the agreement between the supplier and the buyer. Additional remarks:
This standard was proposed by the National Technical Committee for Compressor Standardization. This standard is under the jurisdiction of the Hefei General Machinery Research Institute of the Ministry of Machinery and Electronics Industry. This standard was drafted by the Shenyang Gas Compressor Research Institute. The main drafters of this standard are Zhao Yuncheng, Lu Peiming and Li Guizhou. 3
People's Republic of China
Mechanical Industry Standard
Technical Conditions for Grey Iron Castings for Positive Displacement Compressors JB/T 64311992
Published and distributed by the China Academy of Mechanical Science
Printed by the China Academy of Mechanical Science
(No. 2 Shouti South Road, Beijing
Postal Code 100044)
Sheet 1/2
Word count 6,000
Format 880×1230
First edition in December 1992
First printing in December 1992
Print run 1-500
Price 1.50 yuan
Mechanical Industry Standard Service Network: http:/www.JB.ac.cn61_9
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