This standard specifies the technical requirements of tin-based bearing alloys, the requirements of bearing shells, the technical requirements of the casting process of bearings, and the inspection of the casting quality of bearings. This standard is applicable to the casting of tin-based alloy bearings such as marine diesel engines and ship shafting bushings. CB/T 102-1996 Technical conditions for casting of tin-based alloy bearings CB/T102-1996 Standard download decompression password: www.bzxz.net

Shipbuilding Industry Standard of the People's Republic of China
CB/T 102—1996
Technical Conditions for Casting Tin-Based Alloy Bearings
Published on September 3, 1996
Published by China State Shipbuilding Corporation
Implemented on April 1, 1997
CB/T102—1996
This standard has revised CB/Z102—68 in terms of technical requirements and quality inspection. From the date of entry into force, this standard will replace CB/Z102—68.
This standard was proposed by the Technical Committee on Application Technology of Marine Materials of the National Technical Committee on Marine Ship Standards. This standard is under the jurisdiction of the 725th Institute of the 7th Research Institute of China State Shipbuilding Corporation. The drafting unit of this standard: Hudong Shipyard. Participating drafting units: Dalian Marine Diesel Engine Factory and the 12th Research Institute of China State Shipbuilding Corporation.
The main drafters of this standard are: Zhao Jicheng, Lu Juying, Yu Zhenhai, Zhao Fengyan, Cao Baili, Zhu Yaoming, Wu Jianbo. 1 Scope
Ship Industry Standard of the People's Republic of China
Technical Conditions for Casting Tin-Based Alloy Bearings
CB/T102-1996
Classification Number: U05
Replaces CB/Z102-68
This standard specifies the technical requirements for tin-based bearing alloys, the requirements for bearing base shells, the technical requirements for the casting process of bearings, and the inspection of the casting quality of bearings.
This standard is applicable to the casting of tin-based alloy bearings such as marine diesel engines and ship shafting bushings. 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB228—87 Metal tensile test method
GB231-84 Metal Brinell hardness test method GB/T1174—92 Cast bearing alloy
CB1156—92 Metallographic inspection of tin-based bearing alloy ZBU05006.1～006.16—89 Chemical analysis method of tin-based bearing alloy 3 Technical requirements for tin-based bearing alloy
3.1 Chemical composition
The chemical composition of tin-based bearing alloy is shown in Table 1. Table 1
Alloy grade
ZSnSb11Cu6
ZSnSb7.6Cu3.5Cd1Nio.2
ZSnSb8Cu4
3.2 Mechanical properties
Chemical composition of tin-based bearing alloy
Chemical composition, %
Main components
The mechanical properties of tin-based bearing alloy are shown in Table 2. China State Shipbuilding Corporation approved Cd on September 3, 1996, and the rest 0.10 impurity content, implemented on April 1, 1997. Alloy grade ZSnSb11Cu6 ZSnSb7.6Cu3.5Cd1Nio.2 ZSnSb8Cu4 4 Requirements for bearing shell CB/T102-1996 Table 2 Mechanical properties of tin-based bearing alloys 4.1 The bearing shell material should be low-carbon steel, cast iron and bronze (except aluminum bronze). 4.2 The bearing shell should be processed according to the casting process drawing, and cutting oil or grease should not be used during processing. The surface of the cast tin-based alloy should be smooth and the roughness should not be lower than R. =12.5μm, no looseness or sand holes. The burrs on the two end faces and the mating surface of the base shell should be smoothed. 4.3 The casting surface of the cast iron base shell should have a dovetail groove, and the sharp angle of the dovetail groove must be rounded. 5 Casting process technical requirements for tin-based alloy bearings 5.1 Preparation of the bearing base shell before casting
5.1.1 Degreasing
5.1.1.1 The degreasing of the low-carbon steel bearing base shell is carried out by immersing the base shell in an alkali solution with a temperature of 80-100C. It can also be degreased in a sealed trichloroethylene steam pool (steam temperature 95℃). After degreasing, the casting surface of the base shell is required to be evenly infiltrated by clean water. If there are oil spots, degreasing should be done again.
5.1.1.2 The degreasing of the cast iron bearing base shell is generally carried out by sandblasting to remove oil stains and free carbon. After sandblasting, the casting surface of the base shell must have a silver-gray luster.
5.1.1.3 The casting surface of the bronze bearing shell is cleaned and degreased with detergent. 5.1.1.4 After the bearing shell is degreased (except for the sandblasted cast iron shell), it should be immediately placed in running hot water with a temperature above 70°C for cleaning. 5.1.2 Rust removal
5.1.2.1 Place the low-carbon steel bearing shell in an industrial hydrochloric acid solution for pickling and rust removal until the surface shows a silver-gray luster. After pickling, the bearing shell is cleaned with running water. 5.1.2.2 The cast iron bearing shell is rust-free by sandblasting. Tin plating should be carried out in time after sandblasting. If it exceeds 4 hours, it should be sandblasted again. 5.1.2.3 The bronze bearing shell does not need to be pickled. 5.1.3 Applying solvent
Quickly immerse the cleaned bearing shell in a solvent (saturated zinc chloride solution containing 5% ammonium chloride) and immediately take it out and dry it. 5.1.4 Apply protective layer
Apply a layer of chalk paint with a brush to the surface that is not allowed to be tinned. 5.1.5 Preheating
The bearing base shell needs to be preheated before tinning. The temperature is 150~200℃ and the time shall not be less than 15min. 5.1.6 Tinning
5.1.6.1 Tinning uses 99.9% pure tin. 5.1.6.2. The tinning of the bearing base shell can be carried out by immersion or brushing, but the immersion method is recommended. 5.1.6.3 The immersion method is stipulated as follows:
a) The temperature of the tin liquid is controlled at 280~300℃; b) The bearing base shell coated with zinc chloride and preheated is completely immersed in the tin liquid. When the temperature of the tin liquid returns to the control temperature and is kept warm for 5~10min (but not more than 45min), the bearing base shell can be taken out. Before taking out, the slag on the surface of the tin liquid must be carefully removed; 2
CB/T102—1996
c) After the bearing base shell is taken out of the tin liquid, the remaining tin should be brushed off with a soft brush dipped in water. The tin-plated surface should be bright, uniform, clean, and silver-white mirror-like. The tin liquid should be in a flowing state on the casting surface and should not have an oxidized color; d) If there are spots that cannot be plated with tin, scrape them with a scraper or grind them with a grinding wheel, then brush them with zinc chloride solution and re-tin them; e) If there is slag adhering to the tin-plated surface of the base shell, use a brush dipped in zinc chloride solution to quickly brush it off, and then put it into the tin liquid for tin plating; f) The tinned base shell should be cast quickly to reduce oxidation on the surface of the tin-plated layer and ensure that the tin layer is liquid during casting. 5.2 Melting of bearing alloys
5.2.1 Before melting the bearing alloy ingots, the manufacturer's finished product certificate, chemical composition report and chemical composition re-inspection report after storage must be held. bzxz.net
5.2.2 Before feeding, the alloy grade on the drawing must be checked. 5.2.3 The melting temperature of the bearing alloy is 400-430℃. 5.2.4 After the bearing alloy is melted, it must be stirred frequently and refined with dehydrated ammonium chloride (the amount is 0.05%-0.1% of the alloy weight), and then poured. In the continuous melting and pouring process, each feed needs to be refined with ammonium chloride once, and the amount of ammonium chloride is calculated according to the feed amount.
5.3 Pouring and cooling
5.3.1 The casting of the bearing bushing generally adopts the centrifugal casting method or the static casting method, but the centrifugal casting method is recommended. 5.3.2 The centrifugal casting process is as follows:
a) The casting tools and molds in contact with the alloy liquid must be preheated to 150-200℃. b) The centrifuge should operate normally and be adjusted to an appropriate speed according to the bearing size. The speed is calculated according to formula (1): 60007000
Where: n-
Bearing speed, r/min;
d——Bearing inner diameter, mm.
For bearings with larger diameters, the coefficient in the formula should be taken as the upper limit, (1)
c) After the bearing base shell is installed, start the centrifuge, and after the speed stabilizes, pour the alloy liquid into the rotating bearing base shell. The pouring temperature of the alloy is controlled at 390-410℃, and the alloy liquid flow should be rapid and continuous, and must not be interrupted. d) After pouring, the water spray cooling device must be started immediately to quickly cool the bearing to 100-120℃, and then remove it for air cooling. e) When removing the bearing from the centrifuge, avoid vibration damage to the bearing. 5.3.3 The static pouring process is as follows:
a) The tools and molds used for pouring must be preheated to 150-200℃; b) The alloy should be poured quickly after it comes out of the furnace, and the alloy pouring temperature should be controlled at 400-420℃. The alloy liquid should be as short and thick as possible during pouring to avoid air being drawn in:
c) During the pouring process, the preheated steel bars can be used for up and down pounding, and the alloy liquid can be continuously added. At the same time, the alloy liquid surface can be kept liquid by heating with oxygen and acetylene flames to enhance the shrinkage compensation effect; d) After pouring, the back of the base shell is cooled by wind or water (from bottom to top). 6 Inspection of bearing casting quality
6.1 Inspection of bonding layer defects
The bonding layer adhesion defects of tin-based alloy bearings with an alloy layer thickness of not less than 2mm shall be inspected by ultrasonic instruments in accordance with the provisions of Appendix A of GB/T1174.
6.2 Surface defect inspection
The pinholes, cracks and edge bonding defects on the finely machined surface of tin-based alloy bearings are inspected by dyeing flaw detection. 6.3 Mechanical property inspection
6.3.1 The mechanical property inspection of cast tin-based bearing alloys is generally based on the hardness of the alloy layer. The hardness of the single-cast specimen shall be in accordance with the provisions of CB/T102-1996
GB/T1174. The hardness test method shall be carried out in accordance with GB231. For bearings with an alloy layer thickness of not less than 2mm, the hardness shall comply with the provisions of Table 2.
6.3.2 If the purchaser requires the inspection of the tensile properties of the alloy, the metal mold test block shall be cast according to Figure 1, and the test method shall be carried out in accordance with GB228. Its performance shall comply with the provisions of Table 2.
6.4 Metallographic inspection
6.4.1 The metallographic test shall be carried out on a furnace test block with a size of 40mm×40mm×10mm. 6.4.2 The metallographic structure of tin-based bearing alloys shall be inspected in accordance with the provisions of CB1156. 6.5 Chemical composition inspection
6.5.1 Chemical composition samples are generally taken from thin test pieces cast from the same furnace alloy. 6.5.2 Chemical analysis methods shall be carried out in accordance with ZBU05006.1~006.16. 6.5.3 The chemical composition shall comply with the provisions of Table 1. 165
Figure 1 Metal mold test block
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