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Cast bearing metals
1 Subject content and applicable scope
This standard specifies the technical requirements and inspection rules for cast tin-based, lead-based, copper-based and aluminum-based bearing metals.
This standard is applicable to the manufacture of metallic multilayer plain bearings with tin and aluminum-based integral plain bearings.
2 Normative references
GB 228 Metallic tensile testing
GB 231 Metallic materials - Brinell hardness test
GB 1173 Specification for cast aluminium metals
GB/T 1176 Specification for cast copper metals
GB 1198 Methods for chemical analysis of aluminum
GB 3260.1~3260.9 Methods for chemical analysis of tin
GB 4103.1~4103.12 Methods for chemical analysis of lead-base metals
GB 8002 Methods for chemical analysis of tin bronze
YB 55 Methods for chemical analysis of aluminum bronze
3 Designation representation of metals
The designation of cast bearing metals is composed of the chemical symbols of base metal elements and main metal elements. The main metal element is followed by a number indicating its nominal percent content, which is the round-off integer of this element's average percent content. If the nominal percentage content of metal elements is not less than 1, the number is expressed as an integer. If the nominal percentage content of metal elements is less than 1, the number is generally not marked. If necessary, it can be expressed as one decimal.
The letters "Z" is respectively (the first letter of Chinese phonetic alphabets "Zhu” indicates the cast metal] added before the metal designation.
In case of more than two metal elements, it is not necessary to list all metal elements in the designation except for the essential characteristics of the metals.
The main metal elements in the designation are arranged in descending order of nominal percentage content. When their nominal percent content is equal, they are arranged alphabetically according to their chemical symbols, but for copper-based metals, the elements characterizing the metal series shall be followed closely by the base elements.
4 Technical requirements
4.1 See Table 1 for chemical composition of cast bearing metals
4.2 See Table 2 for the mechanical properties of cast bearing metals.
4.2.1 Separately cast specimens for cast tin-based and lead-based bearing metal hardness shall be as shown in the Figure.
Requirements for hardness determination: HB10/250/60
Diagram of cast tin-based and lead-based bearing metal hardness
4.2.2 The allowable bond defects (stripper) in the bond transition layer between cast tin-based and lead-based bearing metals and backings (bad bond or no bond between tin-based and lead-based bearing metals and backings) can be inspected in accordance with Sub-clause A7 of Annex A (Reference).
4.2.3 Separately cast specimens with the mechanical properties of cast copper-based bearing metal shall be in accordance with GB 1176.
4.2.4 Separately cast specimens with mechanical properties of cast aluminium-based bearing metal shall be in accordance with GB 1173.
4.2.5 The cast-on specimens can also be used for testing the mechanical properties of cast bearing metals.
4.3 In addition to the above, other special requirements such as mechanical properties and physical properties shall be put forward for the bearing metals by the buyer in the drawings or related technical documents or agreed between the supplier and the buyer.
5 Test methods and inspection rules
5.1 Chemical composition
5.1.1 The chemical composition of metals shall be tested in accordance with GB 3260.1~3260.9, GB 4103.1~4103.12, GB 8002 and YB 55. Other methods may be adopted under guaranteed analysis. In case of any dispute, chemical method is adopted for arbitration.
5.1.2 The chemical composition shall be inspected as per smelting furnace or according to the requirements of the buyer. The specimens of the chemical composition can be taken from castings (including cast-on specimens).
5.1.3 For chemical composition inspection, one specimen shall be delivered for the first time. If the analysis result meets the requirements of Table 1, the chemical composition is qualified. Otherwise, another specimen is allowed to be delivered. If the analysis results meet the requirements in Table 1, the chemical composition of the metal in smelting furnace is qualified; otherwise, unqualified.
5.1.4 Only the main elements are analyzed for chemical composition inspection, and the content of other elements can be checked as required by the buyer.
1 Subject content and applicable scope 2 Normative references 3 Designation representation of metals 4 Technical requirements 5 Test methods and inspection rules Annex A Metallic multilayer plain bearings - Bond test - Non-destructive ultrasonic testing of bond defects of bearing metal layer thickness greater than or equal to 2 mm (Reference) Annex B Multilayer plain bearings - Bond test - Determination of bond strength for bearing metal layer thickness greater than or equal to 2 mm (Reference) Additional explanation
试样 图B2试验装置 试验时应注意，在靠近试样结合处肩部的轴承内边和外边的0.1 mm范围内的结合表面(参见图B1)。在试验过程中，不允许受试验装置的阻碍，应确保载荷垂直地作用于结合表面。 B5求值方法 对某一牌号的轴承合金，其结合强度随合金层厚度增加而增加，当合金层增加到某一值时，其结合强度值保持不变，即不再随厚度增加而增加，此时的合金厚度值称为极限值，它是这种牌号轴承合金的特征值。此时的结合强度为绝对结合强度，见图B3。 当低于极限厚度值，结合强度随厚度的减少呈线性下降，此范围内的结合强度称为相对结合强度(参见图B3)。 在结合表面范围内使轴承合金层脱离衬背所需的最大载荷Fmax测得之后，按公式(B1)计算结合强度并根据下述两条件予以评价，即： a. 当层厚度大于或等于极限值时，所求得的值与结合强度的绝对值相当。 b. 当层厚度小于极限值时，如图B3所示，所求得的值就是相对结合强度。
结合强度 相对结合强度 绝对结合强度 图解值 实测值 合金层厚度 图B3轴承合金层厚度与结合强度的关系原理图 B6标记 在本附录范围内，抗拉试验(简称T)按下列顺序标记： 如：试验面积为100 mm2，标记为GB/T 1174/T 100。 B7试验报告 试验报告可根据供需双方协商来书写。其内容如下： a. 试样数量； b. 滑动轴承的尺寸和材料； c. 检测用轴承合金的厚度； d. 检测的表面积； e. 试样断裂时的最大施加载荷； f. 试样断口的描述； g. 结合强度； h. 试验条件； i. 轴承制造厂试验日期。 附加说明： 本标准由中华人民共和国机械电子工业部提出。 本标准由机械电子工业部沈阳铸造研究所归口。
