JB/T 9730-1999 This standard is a revision of ZB J94 007-88 "Metallographic inspection of diesel engine fuel injection nozzle parts, fuel injection pump plunger parts, and fuel injection pump outlet valve parts". During the revision, only editorial changes were made according to relevant regulations, and the main technical content remained unchanged. This standard specifies the inspection of the metallographic structure of diesel engine fuel injection system fuel injection nozzle parts, fuel injection pump plunger parts, and fuel injection pump outlet valve parts (effective thickness of parts is less than or equal to 12mm) after heat treatment. This standard is applicable to the metallographic inspection of GCr15 steel precision parts; metallographic inspection of alloy structural steel needle valve body carburizing and heat treatment; metallographic inspection of W6Mo5Cr4V2 and W18Cr4V steel needle valves. This standard was first issued in 1976 as NJ 97-76 and first revised in 1988 as ZB J94 007-88. JB/T 9730-1999 Diesel engine fuel injection nozzle assembly, fuel injection pump plunger assembly, fuel injection pump outlet valve assembly metallographic inspection JB/T9730-1999 standard download decompression password: www.bzxz.net

ICS43.060.40
Machinery Industry Standard of the People's Republic of China
JB/T9730—1999
Diesel engine fuel injection nozzle parts, fuel injection pump
Plunger parts, fuel injection pump delivery valve parts
Metallographic examination
Metallographic examination of diesel injector nozzle plungerand delivery valve of diesel fuel injection pump1999-09-17 Issued
State Machinery Industry Bureau
2000-01-01 Implementation
JB/T 9730—1999
2 Reference standards
3GCr15 Metallographic inspection of steel precision parts
4 Metallographic inspection of paint and heat treatment of alloy structural steel needle valve body·Metallographic inspection of 5W6Mo5Cr4V2 and W18Cr4V steel needle valves*
Measurement of effective hardened layer depth of needle body after carburizing or carbonitriding tempering by force method Appendix A (standard appendix)
Correction value of Rockwell hardness of sample C grade
Appendix B (suggestive appendix)
JB/T9730-1999
This standard is a revision of ZBJ94007-88 "Metallographic inspection of diesel engine fuel injection nozzle parts, fuel injection pump plunger parts, and fuel injection pump outlet valve parts". During the revision, the original standard was edited and statically modified, and the main technical content remained unchanged. This standard replaces ZB394007-88 from the date of implementation. The downgraded A of this standard is the standard appendix
The appendix B of this standard is the indicative appendix.
This standard is proposed and managed by the Oil Pump Nozzle Standardization Technical Committee. The drafting unit of this standard: Oil-free Pump Nozzle Research Institute. The drafters of this standard: Zhang Limin, Zhu Xifen. This standard was first issued in 1976 as NJ97-76 and revised as ZBJ94007-88 in 1988. Mechanical Industry Standard of the People's Republic of China
Metallographic examination of diesel injector nozzle plungenand delivery valve of diesel fuel injectiou pap1Scope
JB/T 9730—1999
Replaces ZB J94 007-88
This standard specifies the inspection of the metallographic structure of diesel engine fuel injection system injector nozzle, injection pump plunger and injection pump delivery valve (effective thickness of parts is less than or equal to 12mm) after heat treatment. This standard is applicable to the metallographic inspection of GCr15 steel precision parts; metallographic inspection of alloy structural steel needle valve body carburized and heat treated: metallographic inspection of W6Mo5Cr4V2 and W18Cr4V steel needle valves. 2 Reference Standards
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/T3077—1999
GB/T3080-1982
JB/T7173.1—1993
Taiwan structural steel
High-speed tool wire
Technical specifications for diesel engine fuel injection pump plunger pairJB/T 7174.1—1993
Technical specifications for diesel engine fuel injection outlet valve
JB 7296—1994
YB/T 9—1968
Diesel engine fuel injection nozzle pair: technical specifications, technical conditions for chromium bearing steel
Metallographic inspection of 3GCr15 steel precision pairs
3.1 Technical requirements
3.1.1 Raw materials shall be inspected in accordance with the provisions of YB/T9, but the spheroidized degenerate organization level 2-4 shall be qualified. 3.1.2 The hardness of the finished product shall meet the requirements of JB/T7296, JB/T7174.1 and IB/T7173.1 (see Appendix B for the correction value of the surface hardness of the cylinder) 3.1.3 The metallographic microstructure after heat treatment shall be martensite and undissolved carbide particles, and residual austenite with little salt is allowed to exist. According to the first level diagram (Figure 1~Figure 8) of this standard, 1~4 levels are qualified, and those above 4 levels are unqualified. 3.1,4 The working surface of the finished product of the pair is not allowed to have carbon deficiency, decarburization and other irregular band structures. 3.2 Inspection method
3,2. Sampling position
When the product is inspected between heat treatment sequences, the position is determined by the manufacturer. When evaluating quality, the inspection parts are stipulated as follows: needle valve body, plunger sleeve and oil outlet valve seat are longitudinally aligned along the center line; needle valve, plunger and oil outlet valve are cut in the transverse direction, and the cross section is used as the metallographic surface. Approved by the State Bureau of Machinery Industry on September 17, 1999 and implemented on January 1, 2000
3.2.2 Etching agent
Use 2%~4% nitric acid alcohol solution
3.2.3 Inspection content
a) Needle length of white martensite:
JB/T9730—1999
b) Relative quantity and distribution characteristics of martensite in the self-zone and black martensite:) Quantity and distribution of undissolved chemical particles. 3.2.4 Evaluation method
3.2. 4.1 According to the first level diagram of this standard, compare and evaluate at 500 times magnification. 3.2.4.2 The assessment of the lower qualified level must meet two conditions at the same time: the hardness after tumbling is greater than or equal to 63HRC: troostite or bainite appears in the microstructure. If one of the conditions is not met, it is unqualified. 3.2.4.3 The assessment of the upper qualified level is qualified when the length of the martensite needle in the dead zone is less than or equal to 0.007mm. If it exceeds, it is unqualified.
3.3 Metallographic microstructure classification standardwww.bzxz.net
3.3.1 Martensite classification standard: It is divided into eight levels according to the length of the martensite needle and defective organization, see the first level diagram (Figure 1-Figure 8) and its level description is shown in Table 1.
3.3.2 The corresponding pictures of the 4th and 5th level organizations after full tumbling are shown in Figures 9 and 10, the first level diagram (magnified 500 times)
阁! Grade
Figure 22Grade
Figure 33Grade
Figure 55Grade
Figure 6Grade
JB/T 9730—1999
Figure 44Grade
Figure 66Grade
Figure 88Grade
JB/T9730-1999
Metallographic product microstructure
Hidden needle-shaped martensite + a small amount of fine needle-shaped martensite + final carbide particlesHidden needle-shaped martensite + fine needle-shaped martensite + deep carbide particlesFine needle-shaped martensite + fine needle-shaped martensite + final carbide particlesSmall needle-shaped martensite + final carbide particles. Among them, the needle length of martensite is less than or equal to 0.00 mm. Needle-shaped martensite + woody carbide particles. Among them, the needle length of von Fresnel is greater than 0.017 mm. Needle-shaped martensite + new needle-shaped martensite + a small amount of dissolved carbide particles. Among them, the needle length of martensite is greater than 0.02 mm. Martensite + massive martensite + undissolved carbide particles. Martensite + lower Bainite + undissolved carbide particles. Figure 9 GCr15 steel martensite 4 grade
Corresponding figure after full tempering
4 Metallographic inspection of alloy structural steel needle lubrication, carburization and heat treatment 4.1 Technical requirements
4.1.1 Raw materials shall be inspected in accordance with GB/T3077. Figure 1 Corresponding figure of GCr15 martensite 5 grade
Corresponding figure after full concave tempering
4.1.2 The depth of carburized layer and the hardness of the surface shall meet the requirements of JB/T7296 (the surface correction value of the rigid cylinder is shown in Appendix B. Figure
4.1.3 Carburized layer The microstructure of the carbon layer is fine needle-shaped, needle-shaped martensite, bainite and granular and blocky carbides, and an appropriate amount of residual austenite is allowed. The requirements are as follows:
a) Carbide: According to the second level diagram of this standard (Figure 11~Figure 16), less than or equal to level 4 is qualified: large Ding 4 is unqualified, b) Martensite and residual austenite: According to the first level diagram of this standard (Figure 17-Figure 22), less than or equal to level 3 is qualified, large Ding 3 does not contain whole
4.1.4 Finished product 1 is allowed to have decarburization and other abnormal structures. 4.2 Inspection method
4.2.1 Sampling location
3BT9730—1999
Measurement of carburized layer depth and evaluation of carbon layer microstructure, during inspection between heat treatment processes, the location is determined by the manufacturer. When evaluating product quality, longitudinal shaving is performed along the center line of the part, on the sealing cone surface and the center hole surface. 4.2.2 Etching agent
Use 4% nitric acid alcohol solution.
4.2.3 Evaluation method
4.2.3.1 Effective hardened layer depth measurement method (for carburized or carbon-co-carburized parts, after annealing and tempering, the vertical distance from the surface to the hardness of 550HV, see Figure 23). The measurement method is shown in Appendix A (Standard Appendix). The following methods can also be used:
a Equilibrium state equilibrium method
b) Slow cooling measurement method (the total depth of the carburized layer is measured from the carburized surface to the end of the lower bainite area, see Figure 24 and Figure 25); c) Isothermal quenching measurement method (Isothermal quenching process is: heating at 850℃±10℃, isothermal at 280℃±5℃, isothermal for 5 minutes, water cooling after isothermal repair, the total depth of the carburized layer is measured again until the black tempered martensite begins to appear, see Figure 26 and Figure 27), Note: b) and c) are only applicable to 18Cr2i4WA steel. When there is a dispute over the depth of the carburized layer, the effective hardened layer depth measurement method shall be used. 4.2.3.2 The measurement of the depth of the carburized layer shall be carried out according to Figures 23-27 at a magnification of 100 or 200 times. 4.2.3.3 The evaluation of carbides, martensite and residual austenite is carried out in the tempered state. The most serious field is selected and evaluated according to the second level diagram.
4.3 Metallographic microstructure classification standard
4.3.1 Carbide classification standard: It is divided into eight levels according to the size, shape, quantity and distribution of carbides, as shown in the second level diagram (Figure 11-Figure 16), and its level description is shown in Table 2.
4.3.2 Martensite and residual austenite classification standard: It is divided into six levels according to the size of martensite needles and the amount of residual austenite, as shown in the first level diagram (Figure 17~Figure 22), and its level description is shown in Table 3. Second level diagram (magnified 500 times)
JBT9730—1999
Figure 122nd level
Figure 133rd level
Figure 144th level
JB/T 9730—1999
Figure 155th level
Figure 166th level
Gold machine micro-correction
Few fine granular carbides, evenly distributed granular + few granular carbides, evenly distributed massive + shaped carbides, evenly distributed
Mega + granular carbides, densely distributed, with a tendency to a network-like network of massive + granular carbides, densely distributed, with a network-like network of light large massive carbides, intermittent network layout diagram
JB/T 9730—1999
Third level enlarged map (500 times)
Figure 171 level
Figure 182 level
Figure 193 level
JB/T 9730—1999
Figure 204 level
Figure 215 level
Figure 226 level
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