GB/T 5617-1985 Determination of effective hardened layer depth of steel after induction or flame hardening GB/T5617-1985 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of effective depth of hardening after induction or flame hardening of steelUDC 669.14: 620
.178.1
GB 5617-85
This standard determines the effective depth of hardening (DS) of steel parts after induction or flame hardening and specifies the measurement method of this hardening depth.
This standard is equivalent to the international standard ISO 3754-1976 "Steel-Determination of effective depth of hardening after flame or induction hardening" Scope of application
This standard applies to:
a. The depth of hardened layer after induction or flame hardening is greater than 0.3mm. b. After surface quenching, the hardness of the part at a depth three times the effective hardened layer depth (DS) from the surface must be lower than the limit hardness (HVHL) minus 100.
If this condition cannot be met, a higher limit hardness value may be specified to determine the effective hardened layer depth by agreement between the parties concerned. 2 Nouns and terms
2.1 Limit hardness: A function of the minimum hardness (HV) required on the surface of a part, calculated by the following formula: HV hL = 0.8 × hV Ms
Where: HV-
-Limit hardness:
The minimum hardness required on the surface of a part.
Other limit hardness values ​​may also be used by agreement between the parties concerned. By agreement between the parties concerned, the surface Rockwell hardness method may also be used for determination. In this case, the limit hardness value shall be specified. 2.2 Effective hardened layer depth (DS) after induction hardening or flame hardening: The distance from the surface of the part to the layer where the Vickers hardness is equal to the limit hardness. The load used for hardness measurement is 9.8N (1kgf). With the agreement of the parties concerned, a load ranging from 4.9N (0.5kgf) to 49N (5kgf) can be used. 2.2.1 The effective hardened layer depth after induction hardening or flame hardening is represented by the letters "DS" and the depth unit is mm. The expression of the hardened layer depth is as follows:
For example: the hardened layer is 0.5mm, which can be written as DS=0.5. According to the agreement of the parties concerned, when the load is not 9.8N (1kgf) or other limit hardness values ​​are used, a subscript should be written after the letters DS.
For example: the selected load is 4.9N (0.5kgf), the limit hardness value is 0.9 times the minimum surface hardness value required by the part, and the measured hardened layer depth is 0.6mm, which can be written as DS4.9/0.9=0.6.3 Measurement
The measurement should be carried out in one or more areas on the surface agreed upon by the parties and marked on the drawing. 3.1 Disputed situations
Published by the National Bureau of Standards on November 25, 1985
Implementation on August 1, 1986
GB 5617-85
In controversial situations, the method for determining the effective hardened layer depth after induction quenching or flame quenching specified here is the only method that can be used.
3.2 Measurement principlewwW.bzxz.Net
The effective hardened layer depth is determined by the hardness change curve on the vertical surface cross section, which is obtained on the curve by graphical method. The hardness variation curve is a graph showing the change of hardness on the cross section as the distance from the part surface changes. 3.3 Measurement method
Unless otherwise agreed by the parties concerned, the measurement is generally carried out on the cross section of the part in the quenched state. In the case where the original part cannot be used, the measurement can be carried out on a sample with the same shape, size, steel grade and heat treatment conditions as the hardened part of the part by agreement of all parties. 3.3.1 Preparation of the measuring surface
The part is cut perpendicular to the hardened surface, and the cut surface is used as the inspection surface. The inspection surface should be polished to the size of the hardness indentation that can be accurately measured. During the cutting and polishing process, be careful not to affect the hardness of the inspection surface, and do not allow the edges to form rounded corners. 3.3.2 Determination of hardness
The hardness indentation should be made on one or more parallel lines perpendicular to the surface and within a width of 1.5mm (see figure). The distance between the center of the indentation closest to the surface and the surface (d,) is 0.15mm, and the distance from the surface to the center of each successive indentation should increase by 0.1mm each time (for example, d2-d, should be 0.1mm). When the depth of the surface hardened layer is large, the distance between the centers of the indentations can be larger, but near the limit hardness zone, the distance between the centers of the indentations should still be maintained at 0.1mm. 1.5mm
Location of hardness indentation
3.4 ​​Measurement results
3.4.1 From the drawn hardness change curve, determine the distance from the surface of the part to the hardness value equal to the limit hardness. This distance is the effective hardened layer depth after induction fire or flame quenching. 3.4.2
When there are multiple hardness change curves in an area, the arithmetic mean of the hardened layer depths measured by each curve should be taken as the effective hardened layer depth.
Test report
The test report should include the following parts:
Description of the parts and their heat treatment conditions;
Location of the surface of the parts to be tested,
GB5617—85
Effective depth of hardened layer after induction fire or flame quenching. Additional remarks:
This standard was proposed by the Ministry of Machinery Industry of the People's Republic of China and is under the jurisdiction of the Beijing Institute of Mechanical and Electrical Engineering of the Ministry of Machinery Industry. This standard was drafted by the Shanghai Institute of Materials of the Ministry of Machinery Industry. The main drafters of this standard are Zhou Fuxin and Wang Baogeng. 688
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