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,

barrel 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

Sand mould type Metal mould type

Kind of

alloys

Steel Fe Cu Al Mg Zn Cu Al Mg Zn Casting method

Roughness Nominal value of parameter Ra

μm

Sand

casting

Shell

mold

casting

Sand

casting

Sand

casting

Shell

mold

casting

Sand

casting

Sand

casting

Sand

casting

Sand

casting

Metal

mold

casting

Pressure

casting

Metal

mold

casting

Pressure

casting

Pressure

casting

Pressure

casting

0.2 X X

0.4 X X X

0.8 X X X * *

1.6 X X X X X * * *

3.2 X * X X X X X X X X * * * *

6.3 * * X * X X X X X * * * * *

12.5 X * * * * * * * * * * * * * *

25 X * * * * * * * * * * * * *

50 * * * * * * * * * *

100 * * * * * * *

200 * * * * * *

400 *

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

shall 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 0.2 0.4 0.8 1.6 3.2 6.3 12.5 25 50

100 200

400

Sampling length

0.25

0.8

2.5

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

effective value)%

Number of sampling length

involved in evaluation length

Type of alloys Casting method Tolerance of

average(Percent

of nominal

value) %

2 3 4

5 6

Sand mould casting

Shell mould casting

32 26 22 20 18

Ferrous metals Investment casting

Nonferrous metals All methods +10 -20 24 19 17 15 14

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.

Table 4 Min. size of each side on the surface of specimens

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.