JB/T 8555-1997 Method of indicating heat treatment technical requirements on part drawings
Some standard content:
Machinery Industry Standard of the People's Republic of China
JB/T8555—1997
Technical requirements for heat treatment
Method of representation on part drawings
Published on April 15, 1997
Ministry of Machinery Industry of the People's Republic of China
Implementation on January 1, 1998
JB/T8555—1997
This standard adopts DIN6773 (1976) Part 3 "Marking of heat treatment of steel materials on part drawings - Surface quenching", DIN6773 (1977) Part 4 "Marking of heat treatment of steel materials on part drawings - Carburizing rate and fire" and DIN6773 (1977) Part 5 "Marking of heat treatment of steel materials on part drawings - Nitriding" in a non-equivalent manner. Compared with DIN6773, this standard adds general provisions and relevant provisions on the method of expressing the technical requirements of normalizing, annealing and quenching and tempering (including quenching and tempering) on the part drawings, so as to better meet the actual application of heat treatment technology in my country. This standard has been implemented since January 1998.
This standard is proposed and managed by the National Technical Committee for Heat Treatment Standardization. The drafting units of this standard are: Jiangsu University of Science and Technology, Shanghai Heat Treatment Plant, China Textile Machinery Co., Ltd., Sichuan Danchi Industrial Co., Ltd. The main drafters of this standard are: Huo Shupeng, Dai Qixun, Chen Xuefang, Bo Xintao, Su Xiang, Yin Hanqi. 1
1 Scope
Method of expressing the technical requirements of heat treatment on the part drawings of the People's Republic of China
Method of expressing the technical requirements of heat treatment on the part drawings of steel parts
This standard specifies the method of expressing the technical requirements of heat treatment on the part drawings of steel parts. This standard is applicable to various steel mechanical parts. 2 Cited standards
JB/T8555—1997
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T131—93
GB/T23091
GB231-84
GB181879
GB 434084
GB/T 4342—91
GB5030—85
GB5617-85
GB 945088
GB9451—88
GB/T 1135489
JB/T6050—92
JB/T6956—93
3 General
Mechanical drawing surface roughness code and annotation method Metal Rockwell hardness test methodwww.bzxz.net
Metal Brinell hardness test method
Metal surface Rockwell hardness test method
Metal Vickers hardness test method
Metal micro Vickers hardness test method
Metal small load Vickers hardness test method|| tt||Determination of effective hardened layer depth after induction quenching or flame quenching of steelDetermination and verification of effective hardened layer depth of steel parts carburizing and quenchingDetermination of total hardened layer depth or effective hardened layer depth of thin surface of steel partsDetermination of nitriding layer depth and metallographic structure inspection of steel partsGeneral rules for hardness inspection of heat-treated steel parts
Ion nitriding
3.1The heat treatment technical requirements on the part drawing (hereinafter referred to as technical requirements) refer to the technical indicators that the finished parts should reach in the final state of heat treatment (hereinafter referred to as final state).
3.2The heat treatment technical requirements can be marked with standardized symbols and codes, or with text descriptions. The text descriptions are generally written above the title bar in the lower right corner of the drawing and written together with the technical requirements of other processes. In special cases, it is allowed to be written in the blank space of other parts of the drawing. If it can be marked on the drawing, try to avoid using text descriptions. 3.3The marking of technical requirements must be concise, accurate, complete and reasonable. If there are many technical content requirements and there are other technical standards or technical specifications, in addition to marking the main content, it can be stated that it is implemented in accordance with a certain standard or technical specification. 3.4 The index value of the technical requirements is generally marked with the upper and lower limits in the range representation method, such as 60-65HRC: DC=0.8~1.2. It can also be expressed in the deviation representation method with the lower limit nominal value of the technical requirements plus the upper deviation, such as 60+HRC; DC-0.8+*. In special cases, only the lower limit or upper limit can be marked, such as not less than 50HRC, not more than 229HBS. A unified expression should be used on all part drawings of the same product. 3.5 All surface heat treated parts should be marked with the effective hardening layer depth. Its code, definition and measurement method are shown in Table 1. Approved by the Ministry of Machinery Industry on April 15, 1997
Implemented on January 1, 1998
Surface heat treatment methods
Surface quenching and tempering
JB/T8555-1997
Effective hardened layer depth and measurement method of various surface heat treated parts Table 1
Effective hardened layer depth code
Carburizing or carbonitriding Quenching and tempering
Note: The unit (mm) can be omitted when marking. DC
Definition and measurement method standard
When the depth is greater than 0.3mm, follow GB5617
When the depth is less than or equal to 0.3mm, follow GB9451
When the depth is greater than 0.3mm, follow GB9450
When the depth is less than or equal to 0.3mm, follow GB945l
According to GBT11354
3.6 For parts with local heat treatment, the parts with hardening requirements shall be framed with thick dotted lines on the graph in accordance with the provisions of GB/T131. If it is an axisymmetric part or if it does not cause misunderstanding, a thick dotted line can also be drawn on the outside of the heat treatment part to indicate it; other parts, i.e. transitional parts that can be hardened or not hardened, are indicated by dotted lines, and parts that are not allowed to be hardened or do not need to be hardened do not need to be marked. 3.7 When the hardness test of the part must be carried out at a specified point (part), it shall be indicated by the symbol in Figure 1, and its size shall be consistent with the local heat treatment indication symbol specified in GB/T131. When specifying the location of the hardness measurement point, attention should be paid to the requirements of Chapter 6 of JB/T605092. Figure 1 Hardness measurement point symbol marking method
3.8 If the shape of the part is complex or other reasons (such as easy confusion with other process markings) make it difficult to mark the heat treatment technical requirements, and it is not easy to express them in words, you can add a separate drawing to show it. At this time, the content not related to the heat treatment in the drawing can be omitted. As shown in Figure 2. (a)
Surface monitoring data points
DS Resistance measurement points
Y Part heat treatment technical requirements marking diagram
Part heat treatment marking diagram
H8 Measurement points
Special monitoring and control measurement points
(c) Part B heat treatment technical requirements marking diagram Figure 2 Marking method of heat treatment technical requirements for complex parts JB/T8555-1997
3.9 When marking other mechanical properties requirements (such as strength, impact toughness, etc.) except hardness, the specific technical indicators and sampling methods should be indicated on the part drawing.
3.10 The appearance quality of the heat treatment of parts or the requirements that cannot be expressed in quantitative values are generally described in words. 4 Normalized, annealed and quenched and tempered (including quenching and tempering) parts 4.1 Parts that are subjected to normalizing, annealing or quenching and tempering (including quenching and tempering) as the final heat treatment state are generally marked with hardness requirements. It is usually expressed in Brinell hardness (GB231) or Rockwell hardness (GB/T230). It can also be expressed in other hardness. 4.2 When different parts of the same part have different heat treatment technical requirements, they should be indicated separately on the part drawing. 4.3 Partial heat treatment parts must be stated in the text description of the technical requirements: local heat treatment. And mark the parts and technical requirements to be heat treated on the drawing according to the provisions of 3.4 and 36. See Figure 3. Not more than 30HRC
(a) Range representation
(b) Deviation representation
Figure 3 Marking method for technical requirements of local heat treatment parts 5 Surface quenching parts
5.1 The main technical requirements for marking parts for induction heating quenching and tempering and flame heating quenching and tempering are surface hardness, core hardness and effective hardened layer depth.
5.2 Surface hardness
can be expressed by Vickers hardness (GB4340), surface Rockwell hardness (GB1818) and Rockwell hardness (GB/T230). The marking of surface hardness includes two parts, namely the required hardness value and the corresponding test force, and the selection of the test force is related to the required minimum effective hardened layer depth. When
is expressed in Vickers hardness, the relationship between the minimum surface hardness, the minimum effective hardened layer depth and the hardness test force is shown in Table 2. The test force in the table is the maximum allowable value. A lower test force can also be used instead of the value listed in the table, such as HV10 instead of HV30.3
JB/T8555
5-1997
Relationship between the minimum surface hardness value, minimum effective hardened layer depth and test force when expressed in Vickers hardness Minimum effective hardened layer depth
400~500
Minimum surface hardness
>500-600
>600~700
When expressed in Rockwell hardness, the relationship between the minimum surface hardness, minimum effective hardened layer depth and test force is shown in Table 3 and Table 4. Core hardness
When there is a requirement for the core hardness of surface hardened parts, it should be marked. With the agreement of the relevant parties, it is allowed to use the hardness value after preliminary heat treatment as the standard.
Minimum effective
Deepth of hardened layer
Minimum effective
Deepth of hardened layer
JB/T8555-1997
Table 3 When expressed in Rockwell hardness
Relationship between minimum surface hardness, minimum effective hardened layer depth and test force Minimum surface hardness
>85-88
>68-73
(Expressed in HR·N)
>73-78
Table 4 When expressed in Rockwell hardness A scale or C scale> 54~61
Relationship between minimum surface hardness, minimum effective hardened layer depth and test force Minimum surface hardness
>75-78
Effective hardened layer depth
>78-81
>49-55
>61~67
>55~60
The marking of effective hardened layer depth of surface hardened parts includes three parts, namely depth code (see Table 1), limit hardness value and required depth. See 5.5 for the marking method on the drawing. The limit hardness value can be selected according to Table 5 based on the minimum surface hardness. In special cases, other limit hardness values can also be used, but in this case, the agreed limit hardness value must be indicated after DS. The effective hardened layer depth classification and upper deviation of parts can be referred to Table 6. The effective hardening layer depth of flame quenching should not be less than 1.6mm
Limit hardness value
JB/T8555-1997
5 Surface quenching limit hardness value
Minimum table
63-~64
5 Surface rate fire effective hardening layer depth classification and corresponding upper deviation table 6
Minimum effective hardening layer depth DS
Induction quenching
300-330
335~355
360-385
390-420
425-455
460-480
485-515
520-545
550- 575
580-605
610-635
640-665
670~705
710-730
735~765
770~795
800-835
840-865
Flame quenching
5.5 Marking example
JB/T8555-1997
Figure 4 shows the marking method for local induction heating quenching and tempering. This example means: starting from 15mm±5mm from the shaft end, induction heating quenching and tempering are carried out within a section of 30+mm in length. The surface hardness is 620~780HV30, and the effective hardened layer depth is 0.8~1.6mm. 15-.
620-780HV30
DS500-0.8-1.6
（a） Range representation
DS-.a+.620HS
（b) Deviation representation
Figure 4 Local induction heating quenching and tempering marking method 6 Carburizing and carbonitriding parts
6.1 The main technical requirements for marking parts after quenching and tempering after carburizing and after quenching and tempering after carbonitriding are surface hardness, core hardness and effective hardened layer depth. Other technical requirements (such as metallographic structure of the carburized layer, carbon concentration or hardness distribution of the carburized layer, mechanical properties of the core, etc.) shall be implemented in accordance with the provisions of 3.3.
6.2 Surface hardness
The surface hardness requirements for carburized and quenched and tempered parts and carbonitrided and quenched and tempered parts are usually expressed in Vickers hardness or Rockwell hardness. The corresponding minimum effective hardened layer depth and test force are the same as those for surface hardened parts. 6.3 Core hardness
When there is a requirement for the core hardness of carburized and quenched and tempered parts or carbonitrided and quenched and tempered parts, it should be marked. 6.4 Effective hardened layer depth of carburized layer
The method of expressing the effective hardened layer depth (DC) of carburized and quenched and tempered parts or carbonitrided and quenched and tempered parts on the drawing is basically the same as the effective hardened layer depth DS of surface quenching. The marking method on the drawing is shown in 6.5. The limit hardness value of carburized and quenched and tempered parts or carbonitrided and quenched and tempered parts is constant, usually 550HV1. It can generally be omitted when marking. In special cases, 550HV1 may not be used as the limit hardness value. In this case, the agreed limit hardness value and test force must be indicated after DC. The recommended effective hardened layer depth (DC) and upper deviation after carburizing and tempering or carbonitriding and quenching and tempering are shown in Table 7.7
JB/T8555-1997
Table 7: Recommended effective hardened layer depth and upper deviation after carburizing and quenching and tempering or carbonitriding and quenching and tempering Effective hardened layer depth DC
Upper deviation
6.5 Figure 5 shows the local carburizing marking method, which has different requirements for different parts of the parts. The parts that are required to be quenched and tempered after carburizing are outlined with thick dotted lines. ：Some parts are allowed to be carburized and hardened at the same time or not, depending on whether it is beneficial in the process, indicated by dotted lines; unmarked parts are not allowed to be carburized or hardened, local carburization tempering
57-63HRC
DC-1.2~1.7
Figure 5 Local carburization marking method
7 Nitriding (nitriding) parts
7.1 The main technical requirements for gas nitriding or ion nitriding parts are surface hardness, core hardness and effective nitriding layer depth. Some parts also have nitriding layer brittleness requirements. Other technical requirements (such as nitriding layer metallographic structure, nitriding layer hardness distribution, core mechanical properties, etc.) shall be implemented in accordance with the provisions of 3.3.
7.2 Surface hardness
The surface hardness of the part after nitriding is closely related to the part material and preparatory heat treatment. Under normal process conditions, the hardness range that can be achieved by commonly used nitriding materials can refer to JB/T6956. Surface hardness is usually expressed by Vickers hardness, including Vickers hardness (see GB4340), small load Vickers hardness (see GB5030), and micro Vickers hardness (see GB/T4342). The surface hardness value varies due to different detection methods and different effective nitriding layer depths. It should be accurately selected when marking. When the effective nitriding layer depth is not more than 0.3mm, it shall be implemented in accordance with GB9451, and when it is greater than 0.3mm, it shall be implemented in accordance with GB/T11354. 8
JB/T8555-1997
After consultation and agreement, other hardness detection methods can also be used to express it. 7.3 When there is a requirement for the core hardness of nitrided parts, it should be specially stated. The core hardness is usually allowed to be expressed in Vickers hardness, Brinell hardness or Rockwell hardness based on the test results after preliminary heat treatment. 7.4 Effective nitriding layer depth
The nitriding layer depth marked on the drawing, unless otherwise specified, generally refers to the effective nitriding layer depth (see 3.5). Its expression method is basically the same as DS and DC. The marking method on the drawing is shown in 7.5. When the effective nitriding layer depth DN is measured using a Vickers hardness test force of 2.94N (0.3kgf), the limit hardness value is not marked after DN; when other test forces are used, the test force value should be added after DN, such as DNHV0.5=0.3~0.4. The recommended minimum effective nitriding layer depth (DN) and upper deviation for general parts are shown in Table 8. Table 8 Recommended effective nitriding layer depth and upper deviation Effective nitriding layer depth DN
Upper deviation
Effective nitriding layer depth DN
Upper deviation
The relationship between the minimum effective nitriding layer depth, minimum surface hardness and hardness test force required by the technical requirements is shown in Table 9. The inspection method in the table usually refers to the maximum test force allowed, and a lower test force is allowed to replace the test force specified in the table, such as HV10 instead of HV30. Table 9 Technical requirements for the minimum effective nitriding layer depth, the relationship between the minimum surface hardness and the test force Minimum effective
nitriding layer depth
200-300
>300-400
>400-500
>500-600
>600-700
>700-800
5 Total nitriding layer depth
JB/T8555-1997
The total nitriding layer depth is the total depth of nitrogen penetration, generally referring to the vertical distance measured from the surface to the point where the hardness or structure is no different from the matrix, in mm.
The total nitriding layer depth includes two parts: the compound layer and the diffuse layer. When the compound layer thickness is used instead of the DN requirement for a part, it should be specially stated that the thickness requirement varies with the service conditions of the part. The recommended compound layer thickness and tolerance values for general parts are shown in Table 10. 7.6 Marking example
Figure 6 shows the marking method for nitrided parts. The edge of the nitrided part is marked with a thick dotted line, and the position of the hardness test point is specified. Whether the dotted line part is allowed to be nitrided or not depends on whether it is beneficial to the process and is determined by the process. Nitriding is not allowed for the unmarked part. If anti-seepage is required, it must be stated.
Table 10 Recommended compound layer thickness and tolerance Compound layer thickness
Local nitriding hardness is not less than 800HV30
DN=-0.4-0.6, brittleness is not greater than level 3
Marking method for nitrided parts
Other heat-treated parts
8.1 The other heat-treated parts described in this chapter refer to parts that are in the final state of other heat treatment processes except Chapter 47. mm
The method of expressing the heat treatment technical requirements of other heat-treated parts on the part drawings can refer to the provisions of Chapter 3. 8.2
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