This standard specifies the priority number system. This standard applies to the classification of various quantity values. In particular, when determining the parameters or parameter series of products, the basic series values ​​specified in this standard should be used. GB/T 321-2005 Priority numbers and priority number systems GB/T321-2005 standard download decompression password: www.bzxz.net
This standard specifies the priority number system. This standard applies to the classification of various quantity values. In particular, when determining the parameters or parameter series of products, the basic series values ​​specified in this standard should be used.

1CS17.020
National Standard of the People's Republic of China
GB/T321—2005/IS03:1973wwW.bzxz.Net
Replaces GB/T321—1980
Preferred numbers and preferred number systems
Preferred numbers-Series of preferred numbers(ISO 3:1973,IDT)
Issued on 2005-05-16
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Administration of Standardization of the People's Republic of China
Implementation on 2005-12-01
GB/T321—2005/IS03:1973
This standard is a revised version of GR/T321-1980 preferred numbers and preferred number systems. This standard is equivalent to IS03:1973 "Preferred numbers and priority number systems". This standard makes the following modifications to GB/T 321-1980 "Preferred numbers and priority number systems": - According to CB/T 1.1-2009 "Guidelines for standardization work Part 1: Structure and writing rules of standards", the format of the standard is adjusted: - ISO)3:1973 "Preferred numbers and priority number systems" is equivalent to CB/T 1.1-2009 "Guidelines for standardization work Part 1: Structure and writing rules of standards", the format of the standard is adjusted: - ISO)3:1973 "Preferred numbers and priority number systems" is equivalent to CB/T 1.1-2009 "Guidelines for standardization work Part 1: Structure and writing rules of standards" is equivalent to CB/T 1.1-2009 "Preferred numbers and priority number systems ... This standard was proposed by the National Technical Committee for Standardization of Product Dimensions and Geometry. This standard was drafted by the National Technical Committee for Standardization of Product Dimensions and Geometry. The drafting units of this standard are: China Machinery Productivity Promotion Center of the Mechanical Science Research Institute, Times Group Corporation, Beijing Institute of Metrology and Testing Sciences, Harbin Measurement and Cutting Tool Factory.
The main drafters of this standard are: Gong Xinling, Li Xiaoxiao, Zheng Zhongbin, Wu Xun, Lang Yanmei. The previous versions of the standard replaced by this standard are: GB/T 321—1980.
1 Scope
This standard specifies the priority number system,
priority number and priority number system
GB/T 321-2005/ISO 3:1973
This standard applies to the classification of various measurement values. In particular, when determining the parameters or parameter series of products, the basic series values ​​specified in this standard should be selected.
2 Terms and Definitions
Preferred Numbers Series Preferred numbers are the commonly used rounded values ​​of geometric series of integers with common ratios of 10, 10.10, 10 and V0. and with 10 in the terms. The range of 1i0 listed in Table 1 of the basic series and Table 2 of the supplementary series R80 is consistent with it. This preferred number system can be extended infinitely in both directions. The values ​​in the table can be multiplied by 10 positive integers or negative integers to obtain other decimal terms. 2. 1. 1
Preferred numbers preferred numbers
correspond to the rounded values ​​of the R5, R10, R20, R40 and R80 series (see Table 1, columns 1 to 4 and Table 2). 2.1.2
theoretical valuestheoretical values
values ​​of the successive terms of a theoretical geometric sequence such as [1] and (10), where N is an arbitrary integer. Note: Theoretical values ​​are irrational numbers and are not used in practice. 2.1.3
calculated values
approximate values ​​of the theoretical values ​​to within five significant figures, with the relative error of the calculated values ​​to the theoretical values ​​being less than 1/20000. Note: In making precise calculations of parameter series, the theoretical values ​​may be replaced by meters. 2.1.4
serial numbers
an arithmetic progression indicating the order of priority numbers. It starts with the priority number 1.00, serial number 0. 2.2
designation of seriesAll series of optimal numbers are symbolized by the symbol and begin with the symbol. 3 Priority number system
Basic series basic: series
R5, R10., R20 and R40 are the four series commonly used in the optimal optical number system (see Figure 1) Note 1: The commonly used values ​​of the priority numbers in the basic series have a relative error of 1.26% in the calculation! 1.01 In the specification, the common ratio of each series is: R5: 95--(3/10)::. 60
R10: 4=(510)--1.25
GB/T321-2005/ISO3.1973
R20: g=（/10)112
R409=(/10)x1.06
Note 2: The relative reading difference of the commonly used value is the measured value=the calculated value×100% calculated value
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Supplementary series R80ComplementaryR80 seriesR80 series is called supplementary series (see Table 2), its common ratio 0 = (/10) ~ 1.03, only when the parameter classification is very fine or the priority number in the basic series cannot adapt to the actual situation, can it be considered to use the table
Basic series
Basic series (common value)
Theoretical value
Logarithmic tail
Calculated value
Relative error between basic series and calculated value/%
Basic series (common value)
Table 1 (continued)
Supplementary series R80
GB/T 321—2005/ISO 3:1973
Logarithmic tail
Calculated value
1, o;
Basic series calculated value
Relative error/%
---1, 17
GB/T321—2005/IS03:1973
3.3 Derived series
3.3, 1 Derived series
A derived series is a series derived from the value of each term in the basic series or supplementary series Rr, expressed as Rr/p, the ratio r/ is the graded number of term values ​​in each binary number from 1 to [, 10~, etc. The common ratio of the derived series is:
Qh - y - (0]a = 1awr
The derived series with the same ratio have the same common ratio, but the term values ​​are arbitrary. For example, the common ratio of the derived series is Q—1013—1.25892. Three series with different term values ​​can be derived: 1.00, 2.00, 4.00, 8.00
1.25,2.50,5.00,10.0
1.50.3.15.6.3012.
3.3.2 General Case
Let r be the exponent of the base series, r5, 10.20 or 40. It is also the spacing of the derivative series, that is, the number of terms in the base series to be generated when the derivative series is generated. The derivative series formula is:
In addition, if N is a positive integer, the index of the derived series is: 19:40
Then the derivative series is recorded as:
R(-....-10N.....+
Finally, if π is an arbitrary integer (except zero or integer), the arbitrary term of the derivative series is 1010×10=10(%+)
t161 0s11s08
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