This standard specifies the general principles for the selection of low-temperature chemical heat treatment process methods. JB/T 7500-1994 General principles for the selection of low-temperature chemical heat treatment process methods JB/T7500-1994 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T7500-94
Low-temperature chemical heat treatment process method
General rules for selection
1994-10-25 Issued
Ministry of Machinery Industry of the People's Republic of China
1995-10-01 Implementation
Mechanical Industry Standard of the People's Republic of China
Low-temperature chemical heat treatment process method
General rules for selection
1 Subject content and scope of application
This standard specifies the general rules for the selection of low-temperature chemical heat treatment process methods. JB/T 750094
This standard applies to the selection of low-temperature chemical heat treatment process methods such as gas nitriding, ion nitriding, gas nitrocarburizing, salt bath sulfur nitrocarburizing and electrolytic sulfurization for workpieces made of carbon steel, alloy structural steel, tool steel, stainless steel and cast iron. 2 Reference standards
GB7232
GB8121
JB4155
JB/T6956
ZBJ36006
ZB/TJ36018
3 Terminology
Terms of metal heat treatment process
Terms of heat treatment process materials
Gas ammonia carbonitriding process
Ion nitriding
Gas nitriding treatment of steel
Salt bath sulfur-nitrogen-carbonitriding
3.1 Low-temperature chemical heat treatment
A heat treatment process in which the steel workpiece is kept warm in an active medium at a temperature below Ac, and one or more elements are infiltrated to change the chemical composition, organization and properties of the surface layer.
3.2 Occlusion
Under the action of friction, the two abrasion surfaces of the friction pair adhere to each other, and the relative movement of the friction pair is hindered. 3.3 Seizure
The phenomenon that the friction surface is "cold welded" due to the occlusal surface, and the surface has serious adhesion or transfer, which stops the relative movement. 3.4 Contact fatigue
The process in which the material produces local permanent cumulative damage under the action of cyclic contact stress, and pitting, shallow or deep residue occurs on the contact surface after a certain number of cycles.
3.5 Bending fatigue
The process in which cracks are generated in the workpiece under the action of pulse or alternating bending stress, and the cracks extend to cause fracture. 3.6 Adhesive wear
During the relative movement of the friction pair, the contact surface undergoes plastic deformation, the oxide film on the surface is destroyed, and the wear develops from roughening and abrasion to the transfer of material from one surface to another. 4 General principles for selecting process methods
4.1 Select the process based on the service conditions, failure forms and characteristics of the workpiece layer. 4.1.1 For workpieces made of carbon structural steel or low-alloy structural steel that work under low speed or light load but have wear resistance requirements, gas nitrocarburizing or salt bath sulfur nitrocarburizing should be used in the finished product state. For low-alloy structural steel workpieces, ion nitriding can also be used. Approved by the Ministry of Machinery Industry on October 25, 1994
Implementation on October 1, 1995
JB/T7500-94
4.1.2 Workpieces that bear heavy loads and require high wear resistance and fatigue resistance should use ion nitriding or gas nitriding. 4.1.3 For shaft workpieces that are subjected to medium bending, torsion and certain impact loads, and whose working surfaces are subjected to wear, gas nitriding, salt bath sulfur carburizing or ion lacquering should be used (except for carbon structural steel workpieces). 4.1.4 For workpieces that are subjected to very high bending, torsion and certain impact loads, and whose working surfaces are easily worn (such as high-horsepower diesel engine crankshafts); for workpieces that are subjected to very high bending, torsion and certain impact loads, and have high speeds and high precision (such as coordinate mirror bed spindles, etc.), gas nitriding or ion nitriding should be used. 4.1.5 For workpieces made of alloy structural steel containing chromium, molybdenum and vanadium that are subjected to high contact loads and bending stresses and require small deformation (such as large modulus heavy-duty gear shafts, etc.), deep ion nitriding or gas nitriding should be used. 4.1.6 For workpieces that require friction reduction and high self-lubricating performance, salt bath sulfur nitriding and carbonitriding should be used. 4.1.7 For workpieces that simply require good corrosion resistance, carbon steel can be used for manufacturing and anti-corrosion nitriding, but the compound layer should be dominated by phase, and the thickness of the dense area should be above 10μm.
4.1.8 For workpieces that bear light and medium loads and whose main failure mode is adhesive wear, salt bath sulfur-nitrogen-carburizing or gas nitrogen-carburizing should be used.
4.1.9 For molds (such as high-precision cold stamping molds, cold extrusion molds, stretching molds, plastic and non-ferrous metal forming molds, etc.) and cutting tools (except for carbon tool steel and low alloy tool steel cold working molds with low tempering temperature) whose main failure mode is adhesive wear, salt bath sulfur-hydrogen-carburizing or gas hydrogen-carburizing should be used: molds (such as copper alloy extrusion molds and die-casting molds, etc.) whose main failure mode is adhesive wear should be ion nitriding or gas nitriding.
4.1.10 Low-temperature electrolytic porcelain infiltration is mainly used for workpieces that have been carburized, tempered, or tempered, to reduce the surface friction coefficient and improve the ability to resist scratches and bite. 4.1.11 The comparison of the properties of five low-temperature chemical heat treatment layers is shown in Table 1. For the applicable processes of several typical workpieces (such as gears, shafts, hot and cold molds, etc.), see Appendix A (reference), Appendix B (reference), and Appendix C (reference).
Comparison of properties of five low-temperature chemical heat treatment layers Process name
Gas Nitriding
Ion Nitriding
Salt Bath Nitrocarburizing
Gas Nitrocarburizing
Low-humidity Electrolytic Sulfurization
Process name
Gas Nitrogenation
Ion Hydrogenation
Salt Bath Sulfur-Ammonia-Carbonization
Gas Hydrogenation
Low-temperature Electrolytic Nitrogenation
Friction resistance, anti-seizure
and self-lubricating properties
Anti-phosphine
Wear properties
Fatigue
Contact fatigue
Surface hardness HV0.1 (not less than)| |tt||Carbon structural steel
4.2 Select the process according to the material and technical requirements of the workpiece 4.2.1
Alloy structural steel
Impact fatigue
Alloy tool steel
Hot and cold fatigue
Anti-adhesion
Abrasion resistance
Anti-seizure performance
Excellent, not wear-resistant
Depth of sand layer
General 0.3~0.5. Special 0.5~0.7
General 0.2~0.4, special 0.4~0.8
For carbon steel workpieces, gas nitriding (except anti-corrosion nitriding) or ion nitriding should not be used. Gas nitrocarburizing or salt bath sulfur nitrocarburizing should be used.
JB/T 7500—94
4.2.2 For cast iron workpieces, workpieces such as spring steel with a tempering temperature below 520℃, gas nitrocarburizing or ion nitriding should be used. 4.2.3 For workpieces with complex shapes, deep holes, small holes, narrow slits or hundreds of holes that need to be hardened, ion nitriding should not be used. 4.2.4 For workpieces that require local penetration or local anti-penetration, salt bath sulfur-nitrocarburizing should not be used. 4.2.5 For workpieces that require an effective hardened layer depth greater than 0.35mm, ion nitriding or gas nitriding should be used; for workpieces that require a shallower penetration layer, salt bath sulfur-nitrocarburizing or gas nitrocarburizing or ion nitriding can also be used. 4.3 Select the process according to the size of the workpiece and the production batch 4.3.1 For workpieces with large sizes and mass production, gas nitriding or ion nitriding should be used. 4.3.2 For single product and mass production, gas hydrogen-carbon co-penetration can be selected; for workpieces of different sizes and multiple products, salt bath sulfur-nitrogen-carbon co-penetration is suitable. 4.4 Select process based on comprehensive economic benefits
Considering production efficiency, production cycle, energy consumption, equipment investment, production cost and environmental protection, the process should be reasonably selected according to the factory system, see Table 2.
Table 2 Comparison of comprehensive economic benefits of five low-temperature chemical heat treatment process methods Process name
Gas oxygen purification
Ion nitriding
Salt potential sulfur ammonia carbon co-diffusion
Gas carbon co-diffusion
Low-thief electrolytic dredging
Equipment price
And investment amount
General, investment
is not large
More complicated, investment
is relatively large
Simple, investment|| tt||Investment is small
General·Investment is not large
Simple, investment is small
Production cycle and
Energy saving and material saving potential
Long cycle, high energy consumption, small material saving potential
Short cycle, energy saving is about 1/3 compared with gas nitriding
Short cycle·Energy consumption is lower than gas method
, some workpieces can be made of carbon steel
Made, after co-penetration, it replaces stainless steel and blue steel. The cycle is short. Some workpieces are made of carbon steel. After co-penetration, it replaces stainless steel. The cycle is short and the energy consumption is low. The implementation of low-temperature chemical heat treatment process has good production efficiency, labor parts and pollution to the environment. Generally, after co-penetration, in the oxidation bath, |tt||If the temperature is isothermal, the clean water can be discharged directly. Otherwise, FeSO should be added first. The exhaust port is ignited and the hydrochloric acid is extracted with a solvent first, so that the atmosphere is not polluted. It is better to achieve continuous operation without pollution. The difficulty of production is to refer to the relevant process standards such as ZBJ36006, JB/T6956, JB4155, and ZB/TJ36018. The low-temperature electrolytic sulfurization process can refer to the relevant process.
JB/T7500-94
Appendix A
Low-temperature chemical heat treatment process applicable to gears (reference part)
The low-temperature chemical heat treatment process applicable to gears is shown in Table A1. Table A1
Model efficiency range
Gear load
Low load gear
Medium load gear
500~1000
High load gear
Carbon structural steel, alloy
Structural steel, stainless steel, etc.
Alloy structural steel
Alloy structural steel
Main properties of carburized layer
Carburized layer structure
Surface layer.
phase mainly
surface layer
deep layer
compound mainly
surface layer
compound mainly
recommended process
salt bath nitrocarburizing, gas
gas nitrocarburizing, gas or ion nitriding, etc.
higher than nitriding: deep high ion
diagnostic nitriding, gas island
deep ion nitriding
Appendix B
applicable to shaft Low-temperature chemical heat treatment process for workpieces (reference parts)
The low-temperature chemical heat treatment process applicable to shaft workpieces is shown in Table B1.B1
Workpiece namewwW.bzxz.Net
Tractor crankshaft
High-power locomotive and
Marine oil collector crankshaft
Boring machine and machine tool
Transmission shaft
Gear shaft
Energy regulating rod
Failure form
Fatigue,
Fatigue,
Wear.
Suction,
Wear, fatigue
QT600-3
38CrMoAl
40CrNiMo
35CrNi3W
38CrMoA1
38CrwVA1
38CrMoAi
40CrNiMa
Main properties of carburized layer
Surface hardness HV0.1
≥900
500~600
Fatigue strength limit of gear
Fatigue limit of gear
600~1200
1200~1500
Repair layer depth mm
0.15~0.20
0. 25~0.35
0. 4~0. 6
0. 4~0. 6
Heat limit
200~250
250~330
Recommended process
Gas nitrocarburizing:
Salt bath sulfur carburizing
Ion nitrogen
Gas hidden
Gas nitriding
Ion nitriding
Ion nitriding
Gas high carbonization
Salt bath ammonia carburizing
Salt bath ammonia heat nitriding
JB/T7500—94
Appendix C
Low-temperature chemical heat treatment process suitable for molds (reference)
The low-temperature chemical heat treatment process suitable for molds is shown in Table C1. Table C1
Mold category
High-precision cold stamping die
Drawing die (for stainless steel,
titanium and other metal processing)
Aluminum (or zinc) alloy extrusion
Die and die-casting die
Plastic molding die
Additional instructions:
Main failure forms
Impact fatigue
Adhesion wear
Adhesion wear
Hot and cold fatigue
Adhesion wear
Cr12Mo
Cr12MoV|| tt||W6Mo5Cr4V2
W18Cr4V
Cr12Mo
Cr12MoV
W6Mo5Cr4V2
W18Cr4V
4Cr5MoViSi
3Cr2W8
40Cr,45 steel
Main properties of carburized layer
Surface hardness HV0.1
≥1000
≥900
This standard is proposed and managed by the National Technical Committee for Standardization of Potential Processing. Diffusion layer depth mm
0.08~0.12. Compound
Layer depth ≤5pm
0.080.12. Compound
Layer depth 5~10μm
0.15. Compound
Layer depth>8j4m
0.20~0.25, Compound
Layer depth>8pm
Recommended process
Gas nitrogen and carbon co-repair
Salt-dissolved sulfur, nitrogen and carbon Co-penetration
Salt bath carbon co-filtration
Gas nitrogen-carbon co-painting
High-nitrogen
Salt-soluble sulfur-nitrogen-carbon co-penetration
Gas nitrogen-carbon co-penetration
Salt bath ammonia-carbon co-penetration
Gas ammonia-carbon co-penetration
This standard is drafted by the Wuhan Materials Protection Research Institute of the Ministry of Electrical Machinery Industry, and Zhengzhou Machinery Research Institute and Beijing Electromechanical Research Institute participated in the drafting. The main drafters of this standard are Bu Zhensheng, Hu Yizheng, Chen Xiuyu, Zhong Xiaohui and Lin Feng.The air is not polluted, and the difficulty of realizing continuous operation and production is relatively easy. Please refer to relevant process standards such as ZBJ36006, JB/T6956, JB4155, and ZB/TJ36018 for implementation. The low-temperature electrolytic sulfurization process can refer to relevant processes for implementation. JB/T7500-94 Appendix A Low-temperature chemical heat treatment process applicable to gears (reference part) See Table A1 for low-temperature chemical heat treatment process applicable to gears. Table A1
Model efficiency range
Gear load
Low load gear
Medium load gear
500~1000
High load gear
Carbon structural steel, alloy
Structural steel, stainless steel, etc.
Alloy structural steel
Alloy structural steel
Main properties of carburized layer
Carburized layer structure
Surface layer.
phase mainly
surface layer
deep layer
compound mainly
surface layer
compound mainly
recommended process
salt bath nitrocarburizing, gas
gas nitrocarburizing, gas or ion nitriding, etc.
higher than nitriding: deep high ion
diagnostic nitriding, gas island
deep ion nitriding
Appendix B
applicable to shaft Low-temperature chemical heat treatment process for workpieces (reference parts)
The low-temperature chemical heat treatment process applicable to shaft workpieces is shown in Table B1.B1
Workpiece name
Tractor crankshaft
High-power locomotive and
Marine oil collector crankshaft
Boring machine and machine tool
Transmission shaft
Gear shaft
Energy regulating rod
Failure form
Fatigue,
Fatigue,
Wear.
Suction,
Wear, fatigue
QT600-3
38CrMoAl
40CrNiMo
35CrNi3W
38CrMoA1
38CrwVA1
38CrMoAi
40CrNiMa
Main properties of carburized layer
Surface hardness HV0.1
≥900
500~600
Fatigue strength limit of gear
Fatigue limit of gear
600~1200
1200~1500
Repair layer depth mm
0.15~0.20
0. 25~0.35
0. 4~0. 6
0. 4~0. 6
Heat limit
200~250
250~330
Recommended process
Gas nitrocarburizing:
Salt bath sulfur carburizing
Ion nitrogen
Gas hidden
Gas nitriding
Ion nitriding
Ion nitriding
Gas high carbonization
Salt bath ammonia carburizing
Salt bath ammonia heat nitriding
JB/T7500—94
Appendix C
Low-temperature chemical heat treatment process suitable for molds (reference)
The low-temperature chemical heat treatment process suitable for molds is shown in Table C1. Table C1
Mold category
High-precision cold stamping die
Drawing die (for stainless steel,
titanium and other metal processing)
Aluminum (or zinc) alloy extrusion
Die and die-casting die
Plastic molding die
Additional instructions:
Main failure forms
Impact fatigue
Adhesion wear
Adhesion wear
Hot and cold fatigue
Adhesion wear
Cr12Mo
Cr12MoV|| tt||W6Mo5Cr4V2
W18Cr4V
Cr12Mo
Cr12MoV
W6Mo5Cr4V2
W18Cr4V
4Cr5MoViSi
3Cr2W8
40Cr,45 steel
Main properties of carburized layer
Surface hardness HV0.1
≥1000
≥900
This standard is proposed and managed by the National Technical Committee for Standardization of Potential Processing. Diffusion layer depth mm
0.08~0.12. Compound
Layer depth ≤5pm
0.080.12. Compound
Layer depth 5~10μm
0.15. Compound
Layer depth>8j4m
0.20~0.25, Compound
Layer depth>8pm
Recommended process
Gas nitrogen and carbon co-repair
Salt-dissolved sulfur, nitrogen and carbon Co-penetration
Salt bath carbon co-filtration
Gas nitrogen-carbon co-painting
High-nitrogen
Salt-soluble sulfur-nitrogen-carbon co-penetration
Gas nitrogen-carbon co-penetration
Salt bath ammonia-carbon co-penetration
Gas ammonia-carbon co-penetration
This standard is drafted by the Wuhan Materials Protection Research Institute of the Ministry of Electrical Machinery Industry, and Zhengzhou Machinery Research Institute and Beijing Electromechanical Research Institute participated in the drafting. The main drafters of this standard are Bu Zhensheng, Hu Yizheng, Chen Xiuyu, Zhong Xiaohui and Lin Feng.The air is not polluted, and the difficulty of realizing continuous operation and production is relatively easy. Please refer to relevant process standards such as ZBJ36006, JB/T6956, JB4155, and ZB/TJ36018 for implementation. The low-temperature electrolytic sulfurization process can refer to relevant processes for implementation. JB/T7500-94 Appendix A Low-temperature chemical heat treatment process applicable to gears (reference part) See Table A1 for low-temperature chemical heat treatment process applicable to gears. Table A1
Model efficiency range
Gear load
Low load gear
Medium load gear
500~1000
High load gear
Carbon structural steel, alloy
Structural steel, stainless steel, etc.
Alloy structural steel
Alloy structural steel
Main properties of carburized layer
Carburized layer structure
Surface layer.
phase mainly
surface layer
deep layer
compound mainly
surface layer
compound mainly
recommended process
salt bath nitrocarburizing, gas
gas nitrocarburizing, gas or ion nitriding, etc.
higher than nitriding: deep high ion
diagnostic nitriding, gas island
deep ion nitriding
Appendix B
applicable to shaft Low-temperature chemical heat treatment process for workpieces (reference parts)
The low-temperature chemical heat treatment process applicable to shaft workpieces is shown in Table B1.B1
Workpiece name
Tractor crankshaft
High-power locomotive and
Marine oil collector crankshaft
Boring machine and machine tool
Transmission shaft
Gear shaft
Energy regulating rod
Failure form
Fatigue,
Fatigue,
Wear.
Suction,
Wear, fatigue
QT600-3
38CrMoAl
40CrNiMo
35CrNi3W
38CrMoA1
38CrwVA1
38CrMoAi
40CrNiMa
Main properties of carburized layer
Surface hardness HV0.1
≥900
500~600
Fatigue strength limit of gear
Fatigue limit of gear
600~1200
1200~1500
Repair layer depth mm
0.15~0.20
0. 25~0.35
0. 4~0. 6
0. 4~0. 6
Heat limit
200~250
250~330
Recommended process
Gas nitrocarburizing:
Salt bath sulfur carburizing
Ion nitrogen
Gas hidden
Gas nitriding
Ion nitriding
Ion nitriding
Gas high carbonization
Salt bath ammonia carburizing
Salt bath ammonia heat nitriding
JB/T7500—94
Appendix C
Low-temperature chemical heat treatment process suitable for molds (reference)
The low-temperature chemical heat treatment process suitable for molds is shown in Table C1. Table C1
Mold category
High-precision cold stamping die
Drawing die (for stainless steel,
titanium and other metal processing)
Aluminum (or zinc) alloy extrusion
Die and die-casting die
Plastic molding die
Additional instructions:
Main failure forms
Impact fatigue
Adhesion wear
Adhesion wear
Hot and cold fatigue
Adhesion wear
Cr12Mo
Cr12MoV|| tt||W6Mo5Cr4V2
W18Cr4V
Cr12Mo
Cr12MoV
W6Mo5Cr4V2
W18Cr4V
4Cr5MoViSi
3Cr2W8
40Cr,45 steel
Main properties of carburized layer
Surface hardness HV0.1
≥1000
≥900
This standard is proposed and managed by the National Technical Committee for Standardization of Potential Processing. Diffusion layer depth mm
0.08~0.12. Compound
Layer depth ≤5pm
0.080.12. Compound
Layer depth 5~10μm
0.15. Compound
Layer depth>8j4m
0.20~0.25, Compound
Layer depth>8pm
Recommended process
Gas nitrogen and carbon co-repair
Salt-dissolved sulfur, nitrogen and carbon Co-penetration
Salt bath carbon co-filtration
Gas nitrogen-carbon co-painting
Gas nitrogen-involved
Salt-soluble sulfur-nitrogen-carbon co-penetration
Gas nitrogen-carbon co-penetration
Salt bath ammonia-carbon co-penetration
Gas ammonia-carbon co-penetration
This standard is drafted by the Wuhan Materials Protection Research Institute of the Ministry of Electrical Machinery Industry, and Zhengzhou Machinery Research Institute and Beijing Electromechanical Research Institute participated in the drafting. The main drafters of this standard are Bu Zhensheng, Hu Yizheng, Chen Xiuyu, Zhong Xiaohui and Lin Feng.6
Heat limit
200~250
250~330
Recommended process
Gas nitrocarburizing:
Salt bath sulfur carburizing
Ion nitrogen
Gas hidden
Gas nitriding
Ion nitriding
Ion nitriding
Gas high carbonization
Salt bath ammonia carburizing
Salt bath ammonia heat nitriding
JB/T7500—94
Appendix C
Low-temperature chemical heat treatment process suitable for molds (reference)
The low-temperature chemical heat treatment process suitable for molds is shown in Table C1. Table C1
Mold category
High-precision cold stamping die
Drawing die (for stainless steel,
titanium and other metal processing)
Aluminum (or zinc) alloy extrusion
Die and die-casting die
Plastic molding die
Additional instructions:
Main failure forms
Impact fatigue
Adhesion wear
Adhesion wear
Hot and cold fatigue
Adhesion wear
Cr12Mo
Cr12MoV|| tt||W6Mo5Cr4V2
W18Cr4V
Cr12Mo
Cr12MoV
W6Mo5Cr4V2
W18Cr4V
4Cr5MoViSi
3Cr2W8
40Cr,45 steel
Main properties of carburized layer
Surface hardness HV0.1
≥1000
≥900
This standard is proposed and managed by the National Technical Committee for Standardization of Potential Processing. Diffusion layer depth mm
0.08~0.12. Compound
Layer depth ≤5pm
0.080.12. Compound
Layer depth 5~10μm
0.15. Compound
Layer depth>8j4m
0.20~0.25, Compound
Layer depth>8pm
Recommended process
Gas nitrogen and carbon co-repair
Salt-dissolved sulfur, nitrogen and carbon Co-penetration
Salt bath carbon co-filtration
Gas nitrogen-carbon co-painting
High-nitrogen
Salt-soluble sulfur-nitrogen-carbon co-penetration
Gas nitrogen-carbon co-penetration
Salt bath ammonia-carbon co-penetration
Gas ammonia-carbon co-penetration
This standard is drafted by the Wuhan Materials Protection Research Institute of the Ministry of Electrical Machinery Industry, and Zhengzhou Machinery Research Institute and Beijing Electromechanical Research Institute participated in the drafting. The main drafters of this standard are Bu Zhensheng, Hu Yizheng, Chen Xiuyu, Zhong Xiaohui and Lin Feng.6
Heat limit
200~250
250~330
Recommended process
Gas nitrocarburizing:
Salt bath sulfur carburizing
Ion nitrogen
Gas hidden
Gas nitriding
Ion nitriding
Ion nitriding
Gas high carbonization
Salt bath ammonia carburizing
Salt bath ammonia heat nitriding
JB/T7500—94
Appendix C
Low-temperature chemical heat treatment process suitable for molds (reference)
The low-temperature chemical heat treatment process suitable for molds is shown in Table C1. Table C1
Mold category
High-precision cold stamping die
Drawing die (for stainless steel,
titanium and other metal processing)
Aluminum (or zinc) alloy extrusion
Die and die-casting die
Plastic molding die
Additional instructions:
Main failure forms
Impact fatigue
Adhesion wear
Adhesion wear
Hot and cold fatigue
Adhesion wear
Cr12Mo
Cr12MoV|| tt||W6Mo5Cr4V2
W18Cr4V
Cr12Mo
Cr12MoV
W6Mo5Cr4V2
W18Cr4V
4Cr5MoViSi
3Cr2W8
40Cr,45 steel
Main properties of carburized layer
Surface hardness HV0.1
≥1000
≥900
This standard is proposed and coordinated by the National Technical Committee for Standardization of Potential Processing. Diffusion layer depth mm
0.08~0.12. Compound
Layer depth ≤5pm
0.080.12. Compound
Layer depth 5~10μm
0.15. Compound
Layer depth>8j4m
0.20~0.25, Compound
Layer depth>8pm
Recommended process
Gas nitrogen and carbon co-repair
Salt-dissolved sulfur, nitrogen and carbon Co-penetration
Salt bath carbon co-filtration
Gas nitrogen-carbon co-painting
Gas nitrogen-involved
Salt-soluble sulfur-nitrogen-carbon co-penetration
Gas nitrogen-carbon co-penetration
Salt bath ammonia-carbon co-penetration
Gas ammonia-carbon co-penetration
This standard is drafted by the Wuhan Materials Protection Research Institute of the Ministry of Electrical Machinery Industry, and Zhengzhou Machinery Research Institute and Beijing Electromechanical Research Institute participated in the drafting. The main drafters of this standard are Bu Zhensheng, Hu Yizheng, Chen Xiuyu, Zhong Xiaohui and Lin Feng.
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