MT/T 335-1995 Technical requirements for surface anti-corrosion treatment of single hydraulic props
Some standard content:
Coal Industry Standard of the People's Republic of China
MT/T3351995
Single Hydraulic Prop
Surface Anti-corrosion Treatment
Technical Conditions
Published on December 5, 1995
Implemented on March 1, 1996
Published by the Ministry of Coal Industry of the People's Republic of China Coal Industry Standard of the People's Republic of China
Single Hydraulic Prop
Surface Anti-corrosion Treatment
Technical Conditions
1 Subject Content and Scope of Application
MT/T335--1995
This standard specifies the technical requirements, test methods and inspection rules for the surface anti-corrosion treatment of single hydraulic props for mining. This standard applies to the surface anti-corrosion treatment of various components of single hydraulic props for mining. 2 Reference standards
GB1720 Determination of adhesion of paint films
GB3138
GB5270
GB6459
GB7232
Terms and terms commonly used in electroplating
Test method for adhesion strength of metal coatings (electrodeposition and chemical deposition) on metal substratesAcetate spray test for metal coatings (ASS test)Terms and terms for metal heat treatment processes
GB8264
Coating Technical terminology
GB9789
Sulfur dioxide corrosion test of metal and other non-organic coverings under normal condensation conditionsMT112
2 Single hydraulic props for mining
3 Terms
3.1 Plating (coating) layer
Protective layer formed on the metal surface through surface anti-corrosion treatment processes such as electroplating, chemical plating, metal and non-metal infiltration, aluminum alloy anodizing, metal thermal spraying, chemical oxidation of steel parts, spraying of organic or inorganic coatings. 4 Technical requirements
4.1 General technical requirements
4.1.1 Before plating (coating), the material, size, accuracy and surface defects of the parts shall be inspected according to the drawings and technical documents. Those that fail to meet the requirements shall not be subjected to plating (coating) process.
4.1.2 Parts shall be subjected to surface anti-corrosion treatment according to the requirements of the drawings and technical documents. 4.1.3 The plating (coating) layer on the surface of the parts shall be compatible with the working medium of the pillar and the rubber seals, and no dissolution or other chemical reactions are allowed.
The inner surface of the oil cylinder, the outer surface of the piston, and the mating surfaces and sealing surfaces of the three-way valve, column head and other parts shall be subjected to surface anti-corrosion treatment. 4.1.4
4.1.5 The plating (coating) layer shall not be partially without plating (coating) or expose the intermediate layer. 4.1.6 Except for special requirements, galvanized parts shall be treated with dehydrogenation, passivation or phosphating. 4.1.7 Aluminum metal parts shall be treated with anodizing. 4.1.8 The organic coating on the outer surface of the piston shall have fireproof and antistatic properties. 4.1.9 The quality of the outer surface plating layer within 50mm of the welding affected area may not be assessed. ）It is allowed to have a slightly rough surface layer at the chamfer that does not affect assembly 4.1.10
The Ministry of Coal Industry of the People's Republic of China approved on December 5, 1995 and implemented on March 1, 1996
MT/T335-1995
4.1.11 The quality of the plating (coating) layer on the surface of the process tank does not need to be assessed 4.2 The thickness of the plating (coating) layer shall meet the requirements of the drawings and technical documents. 4.3 Appearance quality
4.3.1 The plating layer shall be fine and uniform, and shall not have defects such as surface roughness, hard thorns, and burnt; dendritic, spongy and striped crystals shall not be produced.
4.3.2 The plating (coating) layer shall not have defects such as cracks, peeling, blistering, and shedding. 4.3.3 Due to different heat treatment, welding, and surface processing conditions, the electroplating layer may have different colors and gloss; slight watermarks are allowed. 4.3.4 The coating should be uniform, smooth, non-sticky, and free of defects such as sagging and bubbles. 4.3.5 The surface of iron and steel oxidized parts is not allowed to be covered with dust; there should be no defects such as film damage and oxidation spots. 4.4 Performance requirements
4.4.1 Corrosion resistance of plating (coating) layer
4.4.1.1 During the acetate spray test, the time for the first red rust spot to appear on the piston and cylinder plating (coating) layer shall not be less than 900 hours, and the time for other parts shall not be less than 800 hours.
4.4.1.2 The dicyandisulfur corrosion test takes 24 hours as a test cycle. The test cycle for the first red rust spot to appear on the piston and cylinder plating (coating) layer shall not be less than 8 cycles, and the plating (coating) layer of other parts shall not be less than 6 cycles. 4.4.2 Wear resistance of plating (coating)
After the qualified plating (coating) parts are assembled into pillars and the life test is carried out according to the provisions of MT112, the thickness of the coating (coating) layer of the oil cylinder and the piston shall not be less than 2/3 of the thickness before the life test.
4.4.3 Elongation of plating (coating) layer
When the elongation of the specimen reaches 0.3%, the plating (coating) layer shall not produce cracks. 4.4.4 Adhesion of plating (coating) layer
4.4.4.1 The adhesion of the coating shall meet the requirements of GB1720 Level 1. 4.4.4.2 The plating (coating) layer shall not be allowed to peel or fall off when the scratch method and heating method are tested. 4.4.5 Porosity of plating (coating) layer
4.4.5.1 The porosity of the plating (coating) layer on the outer surface of the piston and the inner surface of the oil cylinder shall be zero. 4.4.5.2 The diameter of pits or pinholes on the surface of the plating (coating) layer of other parts shall be less than 0.2mm, and the number shall not exceed 15 points/dm2. 4.4.6 Chemical oxidation corrosion resistance of steel parts
The end time of discoloration shall be greater than 20s.
4.4.7 Surface treatment coating after plating
Surface treatment coating after plating shall meet the requirements of 4.4.7.1~4.4.7.2 in addition to the requirements of 4.4.1~4.4.5. 4.4.7.1 Impact resistance
No cracks are allowed in the coating after the impact test. 4.4.7.2 Water resistance
The coating thickness of the sample after the water resistance test shall meet the requirements, and no expansion, looseness, etc. are allowed. 5 Test method
5.1 Appearance quality inspection shall be visually inspected under natural scattered light or white transmission light without reflected light. The illuminance should not be less than 3001x (equivalent to the illuminance of the part placed at a distance of 500mm under a 40W fluorescent lamp). If necessary, it can be observed with a 3-5x magnifying glass. 5.2 Test specimens
Some tests cannot use finished products, and samples that have been treated in the same way as the finished products must be used instead of finished products. The number of test specimens for each test shall not be less than three. 5.2.1 The elongation test specimen uses a rod-shaped specimen that has been treated in the same way as the finished product. 5.2.2 For the test specimens used in the corrosion resistance test, the plunger and the cylinder can be cut from the finished product with a height of 100mm, and cut into two specimens along the diameter. Alternatively, a 100mmX200mm specimen of the same material as the test piece can be selected and treated in the same way as the finished product to obtain the specimen. 2
5.3 Corrosion resistance of plating (coating) layer
5.3.1 Acetate spray test
Carry out in accordance with the provisions of GB6459.
5.3.2 Sulfur dioxide corrosion test
Perform the test in accordance with the provisions of GB9789.
MT/T335-1995
5.4 Wear resistance
Perform the test in accordance with the provisions of Table 4, Item 4, Article 6.2 of MT112, and then measure the thickness in accordance with the method of Article 5.10 of this standard. 5.5 Elongation of plating (coating) layer
Visually observe the specimen when it is stretched to the specified value on the material testing machine. 5.6 Adhesion of plating (coating) layer
The plating layer shall be carried out in accordance with the provisions of GB1720, and the coating layer shall be carried out in accordance with the provisions of GB5270. The scratch method and heating method are used equivalently. The scratch method can be used for the outer surface of the column head, and the heating method can be used for the specimens described in 5.2.2. 5.7 Porosity
5.7.1 Carefully degrease the inspected area with a cotton ball dipped in alcohol. Parts taken directly from the tank do not need to be degreased. 5.7.2 Test solution formula
5.7.2.1 The following formula is used for chromium, nickel-chromium, and copper-nickel-chromium plating: Potassium ferrocyanide
Sodium chloride
Ammonium chloride
Prepared with distilled water
Temperature: room temperature
5.7.2.2 The following formula is used for copper-tin plating: Potassium ferrocyanide
Sodium chloride
Prepared with distilled water
Temperature: room temperature
5.7.2.3 The following formula is used for zinc plating:
Mercuric chloride
Hydrochloric acid (d=1.19)
White gelatin
Prepared with distilled water
Temperature: room temperature
30mL/L
5.7.3 According to the type of electroplating layer, the filter paper soaked with the above test solution is respectively pasted on the parts just out of the tank or the parts that have been degreased and washed and dried with distilled water, so that there is no gap between the filter paper and the surface of the parts. The chrome-plated parts are kept for 10 minutes, the copper-plated parts are kept for 60 minutes, and the zinc-plated parts are kept for 5 minutes. Then the filter paper is peeled off, washed with distilled water and placed on a glass plate to dry. The blue spots on the filter paper indicate that there are pinholes on the coating. The filter paper with pinhole marks is placed on a glass plate with a square centimeter grid, and the porosity of the coating is calculated according to the number of pinholes. 5.8 Post-plating surface treatment coating
5.8.1 Impact resistance
The impact test uses a round-headed object with a diameter of 25mm (weight 1kg) to drop on the test piece from a height of 1m and observe visually. 5.8.2 Water resistance
The water resistance test is to immerse the test piece in tap water with an M10 content of 1% to 2% at room temperature and observe it visually with a measuring tool. 5.9 Chemical oxidation corrosion resistance of steel parts
Use distilled water to prepare 2% CuSO solution, drop 1~2 drops on the workpiece, at 15~25℃, take the change on the workpiece surface as the end point, 3
record the time.
5.10 Thickness measurement
MT/T335-1995
The gage measurement method, instrument measurement method, and metallographic method are equivalent. Regardless of the gage measurement method or instrument measurement method, the coating thickness should be measured on three different sections of the part. 5.10.1 Gage measurement method
Use a special gage or a micrometer accurate to 0.001mm to measure the actual size of the same position before and after plating, and calculate the coating thickness.
5.10.2 Instrument measurement method
Use a non-magnetic coating non-destructive thickness gauge with an error of less than ±5%. 5.10.3 Metallographic method
Put the sample under a metallographic microscope to measure the cross-sectional coating thickness. This method is generally used for arbitration inspection. 6 Inspection rules
6.1 The product surface anti-corrosion treatment inspection is divided into type inspection and factory inspection. 6.2 Type inspection is the responsibility of the quality supervision and inspection department designated by the Ministry of Coal. 6.3 Type inspection must be carried out in any of the following situations: 6.3.1 Newly developed surface anti-corrosion treatment process; 6.3.2
When the surface anti-corrosion treatment process formula is changed; 6.3.3
Electroplating plants or electroplating workshops that conduct surface anti-corrosion treatment of single hydraulic prop parts for the first time or have stopped production for more than three years; 1 When the superior quality management department makes a request; 6.3.4
6.3.5 When the user has major objections to the product quality. 6.4 The various inspections that must be carried out when delivering the product to the user shall be carried out according to the factory inspection items. 6.5 The items for type inspection and factory inspection are shown in Table 1. Table 1
Note: ④v
Inspection items
Acetate spray test
Sulfur dioxide test
Abrasion resistance
Elongation
Binding strength
Porosity
Chemical oxidation corrosion resistance
Impact resistance
Water resistance
Inspection items; ②×
Items not inspected.
Technical requirements
Type inspection
Factory inspection
6.6 Sampling method
MT/T335—1995
6.6.1 The number of specimens required for each inspected item during type inspection is 3. 6.6.2 During the user acceptance, random sampling shall be adopted, and the sampling quantity shall be 2% of the order or delivery quantity, but shall not be less than 5 pieces. The sampling quantity may be reduced through negotiation between the two parties.
6.7 Judgment rules
6.7.1 During the type inspection, if two or more unqualified items of the same batch of test pieces are unqualified, it shall be directly judged as unqualified in the type inspection; if there is one unqualified item, the item shall be doubled for testing. If it is still unqualified, the type inspection shall be unqualified. 6.7.2 During the factory inspection, if three or more unqualified items of the same test piece are unqualified, it can be directly judged as an unqualified product. When one of the inspection items is unqualified, the item shall be doubled for sampling inspection according to the sampling quantity. If the item is still unqualified after double sampling inspection, the batch of products shall be unqualified and the user shall have the right to reject it.
Additional instructions:
This standard is proposed by the Standardization Technical Committee for Coal Mine Special Equipment of the Ministry of Coal Industry. This standard is under the jurisdiction of the Support Equipment Branch of the Coal Mine Special Equipment Standardization Technical Committee of the Ministry of Coal. This standard is drafted and interpreted by the Beijing Mining Institute of the China Coal Research Institute. The main drafters of this standard are Lv Donglin, Ye Daoyi and Li Zhongyuan. Coal Industry Standard of the People's Republic of China
Technical Conditions for Surface Anti-corrosion Treatment of Single Hydraulic Support
MT/T335-1995
Published by China Standards Press
No. 16, Sanlihebei Street, Fuxingmenwai, Beijing
Postal Code: 100045
Tel: 8522112
Printed by Qinhuangdao Printing Factory of China Standards Press Distributed by Beijing Distribution Office of Xinhua Bookstore in various places The copyright is reserved for the store
No reproduction
Format 880×12301/16
First edition in August 1996
Printing sheet 1/2
Number of words 10,000 words
First printing in August 1996
Print run 1-1500
Book number: 155066·2-10489
Price 5.00 yuan
Heading 289-155
5661-91 During the type inspection, if two or more items of the same batch of test pieces fail to meet the requirements, the product will be directly judged as unqualified in the type inspection; if there is one unqualified item, the item will be doubled for testing. If it still fails to meet the requirements, the product will be considered unqualified in the type inspection. 6.7.2 During the factory inspection, if three or more items of the same test piece fail to meet the requirements, the product will be directly judged as unqualified. If one of the test items fails to meet the requirements, the item will be doubled for sampling. If the item still fails to meet the requirements after double sampling, the product will be considered unqualified and the user has the right to reject it.
Additional Notes:
This standard was proposed by the Standardization Technical Committee for Coal Mine Special Equipment of the Ministry of Coal Industry. This standard is under the jurisdiction of the Support Equipment Branch of the Standardization Technical Committee for Coal Mine Special Equipment of the Ministry of Coal Industry. This standard was drafted and interpreted by the Beijing Mining Institute of the China Coal Research Institute. The main drafters of this standard are Lv Donglin, Ye Daoyi and Li Zhongyuan. Coal Industry Standard of the People's Republic of China
Technical Conditions for Surface Anticorrosion Treatment of Single Hydraulic Prop
MT/T335-1995
Published by China Standards Press
No. 16, Sanlihebei Street, Fuxingmenwai, Beijing
Postal Code: 100045
Tel: 8522112
Printed by China Standards Press, Qinhuangdao Printing Factory, Xinhua Bookstore, Beijing Distribution Office, Xinhua Bookstores in various places The copyright is reserved for the store
No reproduction
Format 880×12301/16
First edition in August 1996
Printing sheet 1/2
Number of words 10,000 words
First printing in August 1996
Print run 1-1500
Book number: 155066·2-10489
Price 5.00 yuan
Heading 289-155
5661-91 During the type inspection, if two or more items of the same batch of test pieces fail to meet the requirements, the product will be directly judged as unqualified in the type inspection; if there is one unqualified item, the item will be doubled for testing. If it still fails to meet the requirements, the product will be considered unqualified in the type inspection. 6.7.2 During the factory inspection, if three or more items of the same test piece fail to meet the requirements, the product will be directly judged as unqualified. If one of the test items fails to meet the requirements, the item will be doubled for sampling. If the item still fails to meet the requirements after double sampling, the product will be considered unqualified and the user has the right to reject it.
Additional Notes:
This standard was proposed by the Standardization Technical Committee for Coal Mine Special Equipment of the Ministry of Coal Industry. This standard is under the jurisdiction of the Support Equipment Branch of the Standardization Technical Committee for Coal Mine Special Equipment of the Ministry of Coal Industry. This standard was drafted and interpreted by the Beijing Mining Institute of the China Coal Research Institute. The main drafters of this standard are Lv Donglin, Ye Daoyi and Li Zhongyuan. Coal Industry Standard of the People's Republic of China
Technical Conditions for Surface Anticorrosion Treatment of Single Hydraulic Prop
MT/T335-1995
Published by China Standards Press
No. 16, Sanlihebei Street, Fuxingmenwai, Beijing
Postal Code: 100045
Tel: 8522112
Printed by China Standards Press, Qinhuangdao Printing Factory, Xinhua Bookstore, Beijing Distribution Office, Xinhua Bookstores in various places The copyright is reserved for the storewwW.bzxz.Net
No reproduction
Format 880×12301/16
First edition in August 1996
Printing sheet 1/2
Number of words 10,000 words
First printing in August 1996
Print run 1-1500
Book number: 155066·2-10489
Price 5.00 yuan
Heading 289-155
5661-9
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