GB6060[1].1-97Roughness Comparison Specimens--cast surfaces

 National Standard of the People’s Republic of China GB/T6060.1-1997 equal to ISO2632/III:1979 Roughness Comparison Specimens Cast Surfaces Issued on December 30, 1997 Implemented from July 1, 1990 Issued by Administration of Technology Supervision of the People’s Republic of China National Standard of the People’s Republic of China Roughness Comparison Specimens Cast Surfaces GB/T6060.1-1997 Equal to ISO2632/III: 1979 Instead of GB6060.1-85 1. Scope It specifies manufacturing method of roughness comparison specimens on surfaces of cast metals and alloys, surface feature, classification of specimens and parameters of roughness as well as their evaluation method in this standard. It is applicable to roughness comparison specimens on cast surfaces. The specimens are used for comparing with those cast surfaces of cast metals and alloys with same surface features and same casting method, and cleaning with appropriate method (e.g. shot blasting, sand blasting, barrel polishing etc.) . It is also as reference basis for other special casting process and roughness on cast surface. 2. Standards referred Those terms involved in the following standard will constitute the terms of this standard after referred by this standard. When this standard is published, all versions shown are valid. Any of standards shall be revised, therefore all parties who use this standard should discuss on the possibility to procure the latest version. GB 6062-85 Stylus instruments for the measurement of surface roughness by the profile method--Profile recording instruments and profile meters by the median system. 3. Definition The following definitions are adopted by this standard. Roughness comparison specimens on surfaces of cast metals Specimens of Ra with arithmetic average deviation on known surface profile of cast metals and alloys with specific surface features and casting method. 4. Manufacturing method 4.1 Specimens will be manufactured with following methods a) Male dies of a surface copied by electro casting; b) Male die of a surface copied with plastic or other material; c) Surface manufactured directly with alloys and casting method according to the surface features. 4.2 The surface of original master die for copying specimens must represent features of actual cast surface with roughness characteristics of specific cast metals and alloys as well as casting method (cleaning is acceptable with appropriate method such as shot blasting, sand blasting, 1barrel polishing etc.) and comply with parameters of specified surface roughness. 5. Surface features 5.1 The surface of specimens shall represent roughness features on cast surface from specific cast metals and alloys as well as casting method, not include other surface features than surface roughness (although these features are possible to be permitted for existing on surface of actual casts) such as waviness, defect etc. 5.2 Color of specimen surface shall be the color which is to represent on surfaces of specific cast metals and alloys to appear. 6. Classification and parameters of surface roughness Classification and parameters of surface roughness of specimens shall be in accordance with Table 1 with nominal values. Table 1 Classification and parameters of surface roughness of specimens Casting mould type Kind of alloys Casting method Roughness Nominal value of parameter Ra µm Sand casting Sand mould type Steel Shell mold casting Metal mould type Al Mg Zn Metal mold casting Fe Shell mold casting Cu Cu Metal mold casting Al Mg Zn Sand casting Sand casting Sand casting Sand casting Sand casting Sand casting Pressure casting Pressure casting Pressure casting Pressure casting 0.2 0.4 0.8 1.6 3.2 6.3 12.5 25 50 100 200 400 X X * * * * X X * * * * X X * * * X X * * * * * X X * * * X X * * * * * X X * * * * * X X * * * * * X X * * * * * X X * * * * X X * * * * X X * * * * * X X * * * * * X X * * * * * * X X * * * * * * Note: Mark X means that surface roughness of cast metals and alloys can not reach unless adopt special measure; Mark * means that surface roughness of cast metals and alloys can reach. 7. Evaluation method of roughness 7.1 Taking data Measure to take 25 pieces of data from places with even distribution on the surface of specimens. In case data is in too large difference, the number can be added. Measure instrument 2shall be in accordance with provisions of GB6062. In case measure instrument has a known or given error, it shall be considered. 7.2 Sampling length Sampling length shall be taken in accordance with Table 2. Table 2 Standard values for sampling length Parameters of surface roughness Nominal value Ra µm Sampling length mm 0.2 0.25 0.4 0.8 0.8 1.6 3.2 6.3 12.5 2.5 25 50 8 100 200 25 400 7.3 Tolerance of average Deviation that average of readings versus nominal value may not exceed the nominal value percent given in Table 3. Table 3 Tolerance value of surface roughness comparison specimens Standard deviation (Percent of Tolerance of effective value)% average(Percent Type of alloys Casting method Number of sampling length of nominal involved in evaluation length value) % 2 3 4 5 6 Sand mould casting 32 26 22 20 18 Ferrous metals +10 Shell mould casting -20 Investment casting 24 19 17 15 14 Nonferrous metals All methods 7.4 Standard deviation Standard deviation of average shall not exceed the percent of effective value given in Table 3. Max. Allowance of standard deviation with different evaluation length will be calculated as per the following formula according to number of sampling length involved in evaluation length: In the formula: δ5: Standard deviation of 5 sampling lengths involved in evaluation length; δn: Standard deviation of n sampling lengths involved in evaluation length selected when actually measured; n: Number of sampling length involved in evaluation length selected when actually measured; 8. Structure and dimension 8.1 Specimens shall be taken with structure dimension so as to be easy to compare with cast surface and measure them. 8.2 Min. size of each side on the surface of specimens shall be in accordance with Table 4. 3Table 4 Min. size of each side on the surface of specimens mm Parameters of surface roughness Nominal value Ra µm Specification of specimens 0.2 0.4 0.8 1.6 3.2 6.3 12.5 25 30 50 100 200 400 50 26 Model I Model II Model III 20 17 110 9. Marking Specimens shall be marked with following signs: a) GB/T6060.1-1997; b) Nominal value Ra (µm) of parameters of surface roughness c) Represented type of cast metals and alloys as well as type of casting method; d) Name of manufacturer or registered trade mark; e) Product serial number. 4