JB/T 9206-1999 JB/T 9206-1999 Hot-dip aluminum processing and quality inspection for steel JB/T9206-1999 Standard download decompression password: www.bzxz.net

ICS 25.200
Machinery Industry Standard of the People's Republic of China
JB/T 9206—1999
Technology and quality inspectionfor hot-dipped aluminum coatings on iron or steel
Published on 1999-06-24
State Administration of Machinery Industry
2000-01-01 Implementation
JB/T9206-1999
Scope
Cited standards
Classification of hot-dip aluminum layer
Quality requirements of materials
Hot-dip aluminum process
Hot-dip aluminum process methods
Macroscopic inspection of hot-dip aluminum layer
Determination of coating amount of hot-dip aluminum layer (weighing method) 10 Measurement of thickness of hot-dip lead layer
Evaluation of porosity level of diffusion type hot-dip lead layer 12 Evaluation of crack level of diffusion type hot-dip aluminum layer Objective
13 Evaluation of interface type between diffusion type hot-dip aluminum layer and base metal Mechanical properties test of aluminum parts
15 Sampling and determination of test items
16 Product acceptance
17 Product packaging and labeling
Appendix A (Appendix to the standard) Microscopic evaluation method for pore level of diffusion type hot-dip aluminum layer Appendix B (Appendix to the standard) Microscopic evaluation method for crack level of diffusion type hot-dip aluminum layer Appendix C (Suggestive appendix) Evaluation method for interface type between diffusion type hot-dip aluminum layer and base metal [2
JB/T9206-1999
This standard is a revision of ZBJ36011-89 "Hot-dip Aluminum Process and Quality Inspection for Steel". During the revision, editorial modifications were made according to relevant regulations and the following main technical contents were changed: the legend of the hot-dip aluminum layer thickness measurement method was added: Figure 1, Figure 2, Figure 3; the control index of the chemical composition of hot-dip aluminum layer in Table 1 was appropriately adjusted; the control index of the coating of hot-dip aluminum layer in Table 4 was appropriately adjusted: This standard replaces ZB J36 011--89 from the date of implementation. Appendix A and Appendix B of this standard are the appendices of the standard. Appendix C of this standard is the appendix of the reminder. This standard was proposed and managed by the National Technical Committee for Heat Treatment Standardization. The responsible drafting units of this standard are: Wuhan Institute of Material Protection, Hubei Yunmeng Chemical Machinery Factory. The responsible drafters of this standard are: Zhao Xiaoyong, Wu Yong. This standard was first issued on February 27, 1989. II
1 Scope
Standard of the Machinery Industry of the People's Republic of China
Technology and quality inspection for hot-dipped aluminum coxtngs od lron or stee?This standard specifies the key points of hot-dipped aluminum technology for steel and the quality inspection method of hot-dipped aluminum layer. JB/T9206-1999
Replaces 2B J36 01--89
This standard applies to the quality inspection of hot-dipped aluminum technology and products of carbon steel, alloy steel and cast iron. It does not apply to thin strip and wire products produced by continuous hot-dipped aluminum.
2 Referenced Standards
The provisions contained in the following standards become 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 the parties using this standard should explore the possibility of using the latest version of the following standards. GB/T2281987Metal tensile test method
GB/T1196—1993Aluminum ingot for remelting
GB/T6462—1986Method for measuring the cross-sectional thickness of metal and oxide coatings by microscopeGB/T9790--1988Vickers and Knoop microhardness test for metal coatings and other related coatings3Definitions
This standard adopts the following definitions.
3.1Hot-dip aluminum [liquid aluminizing]
The process of obtaining hot-dip aluminum layer by dipping the steel workpiece into a molten aluminum bath and keeping it warm for a period of time so that aluminum (and other additional elements) are coated and infiltrated into the steel surface.
3.2·Hot aluminum layer
The aluminum and aluminum alloy layer formed on the surface of the steel workpiece by the hot-dip aluminum process. It is divided into immersion-type hot-dip aluminum layer and diffusion-type hot-dip aluminum layer.
3.3 Immersion type hot-dip aluminum layer
The hot-dip aluminum layer obtained by directly hot-dip in aluminum. This layer is mainly composed of an aluminum covering layer, and there is a thin compound layer under the covering layer. 3.4 Aluminum cover [attached aluminum layer]
The surface layer of the immersion type hot-dip aluminum layer. Its composition is basically the same as that of the aluminum bath or layer. 3.5 Diffusion type hot-dip aluminum layer
The hot-dip layer obtained by diffusion treatment after hot dipping in an aluminum bath. It consists of a compound layer and a diffusion layer. 3.6 Effective aluminum dipping area
In the aluminum bath, according to the treatment purpose, the charging area that can make the aluminum bath composition and heating temperature meet the process requirements. 3.7 Fake immersion
Approved by the State Bureau of Machinery Industry on June 24, 1999, implemented on January 1, 2000
JB/T 9206—1999
Only a lead layer is formed on the surface of the aluminum-dipped part, and no compound layer is formed. 3.8 Missing immersion
The phenomenon of partial missing of the immersion type hot-dip aluminum layer in the appearance inspection of aluminum parts. 3.9 Missing paint
The phenomenon of partial missing of the diffusion type hot-dip aluminum layer in the appearance inspection of aluminum parts. 3.10 Coverage of hot-dip aluminum layer
The weight of lead and other alloying elements applied to the surface of the workpiece after hot-dip aluminum, expressed as the amount of increase per unit area (g/mm2). 4 Classification of hot-dip aluminum
4.1 Classification by treatment method
a) Immersion type hot-dip aluminum layer;
b) Diffusion type hot-dip lead layer.
4.2 Classification by coating material type
a) Aluminum layer;
b) Aluminum-silicon alloy layer.
5 Quality requirements for materials
5.1 Steel and iron
The quality requirements for the base material (steel and iron) of hot-dip aluminum parts shall comply with the provisions of the corresponding national standards or industry standards. 5.2 Aluminum ingots
The aluminum content of aluminum ingots for hot-dip aluminum shall not be less than 99.5%. Special grade 1~, special grade 2 or grade 1 aluminum ingots in GB1196 are applicable. Hot-dip aluminum process flow
6.1 Diffusion-type hot-dip aluminum layer process flow
Degreasing-rust removal-pre-plating-→hot-dip aluminum-calibration-cleaning-→inspection. 6.2 Diffusion-type hot-dip aluminum layer process flow
Degreasing-rust removal-pre-plating-→hot-dip aluminum-→calibration-cleaning-→inspection-diffusion treatment-calibration-cleaning-→inspection. 7 Hot-dip aluminum process method
7.1 Degreasing
The oil on the workpiece surface must be completely removed. Low-temperature heating degreasing, alkali cleaning or organic solvent cleaning can be used for degreasing. 7.2 Rust removal
Rust products on the workpiece surface must be completely removed. Mechanical or chemical rust removal methods can be used. 7.3 Pre-plating
The parts that have been degreased, rusted and cleaned must be pre-plated before entering the aluminum bath. The pre-plating method can be a water-soluble wave method, a molten salt method or a gas method.
7.4 Hot-dip aluminum bath
The chemical composition of the effective dip lead should in principle comply with the provisions of Table 1. The hot-dip aluminum bath should generally be sampled and adjusted after 8 hours of use. The scum on the surface of the aluminum liquid 2
JB/T 9206-1999
The bottom molten metal of the bath should also be removed regularly. Table 1 Chemical composition of hot-dip aluminum bath
Interesting layer material category
7.4.2 Hot-dip aluminum overflow
Total amount of other impurities
In principle, the hot-dip aluminum temperature should comply with the provisions of Table 2. Carbon steel parts generally take the lower limit; alloy steel and cast iron parts generally take the upper limit. The temperature deviation of the effective hot zone of the hot-dip aluminum bath is 10°C.
Table 2 Hot dip aluminum bath temperature
Yingyun material category
Pin-silicon
7.4.3 Hot dip aluminum time
Insulation temperature
730-780
680-740
The recommended hot dip aluminum time for carbon steel and low alloy steel parts is shown in Table 3. The hot dip aluminum time for medium and high alloy steel and cast iron parts with the same wall thickness can be increased by 20%~30%
Table 3 Hot dip aluminum time for carbon steel
! Part wall thickness
> 1.0-1.5
> 1.5~2.3
> 4.0-6.0
7.4.4 Cooling after leaving the furnace
Immersion type hot-dip aluminum layer
Hot-dip aluminum layer time
Diffusion type hot-dip aluminum layer
After the door parts are removed from the aluminum bath, use vibration or air blowing to remove excess aluminum liquid on the surface in time, air cool to room temperature, and pay attention to avoid rapid cooling at high temperatures.
7.5 Correction
When the deformation of hot-dip aluminum parts exceeds the tolerance, correction treatment should be carried out. 7.6 Surface cleaning
JB/T 9206—1999
Use mechanical or chemical methods to remove residual slag or other dirt on the surface of hot-dip aluminum parts. After chemical cleaning, they should be cleaned and dried.
.7 Diffusion treatment
7.7.1—Diffusion insulation temperature 850~930℃; insulation time 3~5h. If the layer thickness requirement is the main requirement, the upper limit of the diffusion insulation temperature and time can be taken. If the strength requirement of the base metal is the main requirement, the lower limit of the diffusion insulation temperature and time can be taken. 7.2 The cooling method after diffusion treatment should be selected according to the required mechanical properties of the base metal. Furnace cooling or air cooling: 8 Macro inspection of hot-dip aluminum layer
8.1 Visual inspection
8.1.1 The hot-diffusion aluminum layer should be continuous and cover the base metal surface well. 8.1.2 The surface of the impregnated hot-dip aluminum layer shall not have defects such as slag, dull color, false impregnation, and leakage that obviously affect the appearance quality. 8.1.3 The surface of the diffusion-type hot-dip lead layer shall not have defects such as leakage, cracks, and peeling. 8.2 Scratch test
8.2.1 Scratch test of the impregnated hot-dip aluminum layer Use a hard knife and apply appropriate pressure. Scratch the flat part until it penetrates the surface aluminum blue layer. The aluminum coating layer should not peel or fall off beyond 2.0mm on both sides of the scratch line. 8.2.2 Scratch test of the diffusion-type hot-dip aluminum layer Use a tight and hard knife tip and apply appropriate pressure to scratch (or manually saw) the flat part until it penetrates the compound layer. The compound layer should not peel or fall off beyond 2.0mm on both sides of the scratch line (or sawing line). 8.3 Deformation test
Use a ruler, vernier caliper, micrometer, etc. to measure the deformation of the hot-dip aluminum parts, such as deflection, elongation, and thickening. 9 Determination of coating amount of hot-dip aluminum layer [Weighing method] 9.1
The coating amount of hot-dip aluminum layer shall comply with the provisions of Table 4. Table 4 Coating amount of hot-dip aluminum layer
Immersion type
Coating type
Coating material
9.2 Cut the sample from the workpiece by mechanical method and select the preparatory sample of the same batch of materials as the workpiece. The sample is degreased, derusted, and dried according to the same hot-dip aluminum process as the workpiece. It is weighed before and after hot-dip aluminum, and the coating amount per unit area of ​​the hot-dip aluminum layer is calculated. 10 Measurement of the thickness of hot-dip aluminum layer
The thickness of the hot-dip aluminum layer shall comply with the provisions of Table 5. 10.13
Immersion type
Diffusion type
10.2 Microscope measurement method
10.2.1 Sample preparation
JB/T 9206—[999
Table 5 Thickness of hot-dip aluminum layer
Pre-layer material
Aluminum-silicon
The cross-section preparation of the thickness measurement sample shall be carried out in accordance with GB/T6462. The recommended etchants for indicating the thickness of hot-dip aluminum layer are shown in Table 6. Table 6 Etching agents for indicating the thickness of hot-dip aluminum layer
Diffusion agent
Nitric acid solution (d-1.42) 4mL
95% ethanol solution 96 mL
Nitric acid solution ((-[.42)
95% ethanol solution 85mL
Hydrogen peroxide solution (d-1,14)
10.2.2 Determination of the measurement field
Scope of application
Interface line and organization display of hot-dip aluminum layer of various types of steel and iron Diffusion type hot-dip aluminum layer interface line and organization display of various types of steel and iron Divide the sample into six equal parts according to the cross-sectional length, and use the middle five 10.2.3 Measurement of float value
Method for determining the field of view of hot-dip aluminum sample
Measure the maximum and minimum thickness values ​​of the hot-dip aluminum layer in each measurement field of view, see Figure 2 and Figure 3. 10.2.4 Result calculation
Take the 10 measurement values ​​(five maximum thickness values) measured in five measurement fields as the measurement field of view. The thickness of the hot-dip aluminum layer is determined by the arithmetic mean of the value 3m and the five minimum thickness values ​​6ml.
10.3 Thickness gauge detection method
10.3.1 A non-destructive thickness gauge suitable for measuring the thickness of the non-magnetic layer on the steel substrate can be used. 10.3.2 When measuring the thickness, take the average of the five-point readings at each detection position as a measurement value. The three measurement values ​​of each test piece should comply with the provisions of Table 5.
Jinfu Yi Layer||t t||JBT9206—1999
Hot-dip aluminum layer after cleaning
Compound layer
Figure 2 Hot-dip aluminum layer thickness measurement method
Hot-dip aluminum layer after expansion
Compound layer
Diffusion layer
Metal matrix
Metal matrix
Figure 3 Diffusion type hot-dip aluminum layer thickness measurement method
10.4 Arbitration
JB/T 9206—1999
When there is a dispute over the thickness measurement results of the thickness gauge detection method, the results of the microscope measurement method shall prevail. 11 Evaluation of the porosity level of the diffusion type hot-dip aluminum layer 11.1 The porosity level evaluation method of the diffusion type hot-dip aluminum layer shall be carried out in accordance with Appendix A (Appendix to the standard). 11.2 The qualified porosity level is determined according to the product use conditions. Generally, porosity levels 1 to 3 are qualified and levels 4 to 6 are unqualified. 11.3 The thickness of the porous layer shall not be greater than three quarters of the thickness of the hot-dip aluminum layer. 12 Cracks in the diffusion type hot-dip aluminum layer Grade Assessment 12.1 The assessment method for the grade of cracks in the diffusion-type hot-dip aluminum layer shall be carried out in accordance with Appendix B (Appendix to the Standard). 12.2 The grade of cracks in the diffusion-type hot-dip aluminum layer of carbon steel and low alloy steel (Series A) shall be assessed in accordance with Table B1 and Figure BI; the grade of cracks in the diffusion-type hot-dip aluminum layer of medium and high alloy steel (Series B) shall be assessed in accordance with Table B2 and Figure B2. The qualified grade of cracks shall be determined according to the use conditions of the product. Generally, cracks in Series A are qualified at grades 0 to 3, and unqualified at grades 4 to 6; cracks in Series B are qualified at grades 1 to 4, and unqualified at grades 5 to 7. 12.3 The crack depth shall not be greater than three-quarters of the thickness of the hot-dip aluminum layer. 13 Assessment of the interface type between the diffusion-type hot-dip aluminum layer and the base metal 13.1 The interface type between the diffusion-type hot-dip aluminum layer and the base metal is divided into five types according to the shape of the interface of the hot-dip aluminum layer. The assessment method shall refer to Appendix C (Prompt Record).
13.2 In principle, it is stipulated that Type A, Type B, and Type C are qualified; Type E is unqualified; whether Type D is qualified or not can be agreed upon by the user and the manufacturer according to the product use conditions.
14 Mechanical properties test of hot-dip aluminum parts
14.1 Tensile test
14.1.1 Cut the sample from the hot-dip aluminum part by mechanical method (retain the surface hot-dip aluminum layer) or take the sample from the same batch of materials and treat it with the workpiece under the same hot-dip aluminum operation conditions.
14.1.2 The preparation of the sample and its tensile test method shall be carried out in accordance with GB/T228 or relevant regulations. 14.1.3 When calculating the strength, the surface thickening size caused by the hot-dip aluminum process should not reach the cross-sectional size of the added test piece. 14.2 Microhardness test
The microhardness test of the hot-dip aluminum layer shall be carried out in accordance with GB 9790. 14.3 Matrix performance test
The mechanical performance test items and technical indicators of the base metal of hot-dip aluminum parts shall be agreed upon by the user and the manufacturer in the product ordering technical conditions. [S Determination of sampling and test items
15.1 At least three pieces shall be randomly selected from a batch of hot-dip aluminum parts with the same specifications and dimensions that have passed the visual inspection and are delivered at one time according to the order contract. 15.2 Each piece shall be subjected to hot-dip aluminum layer thickness measurement, porosity level assessment, crack level assessment and mechanical performance test; the number of sampling pieces can also be determined by negotiation with the user based on specific circumstances. Sampling location and test items. It is allowed to replace the measurement of the hot-dip aluminum layer thickness with the measurement of the hot-dip lead layer coating; it is allowed to replace the scratch test with the assessment of the interface type between the hot-dip aluminum layer and the base metal. 16 Product Acceptance
When delivering, the product shall be inspected and accepted according to this standard and a test report and product certificate shall be provided. If the product does not meet any technical requirements in Chapter 8 to Chapter 12 of this standard, Chapter 14 or Chapter 15 of JB/T9206-1999, the user shall have the right to reject or return the product. 17 Product Packaging and Marking
17.1 Packaging
The hot-melt aluminum products shall be properly packaged to prevent damage and rust. 17.2 Marking
Hot-dip aluminum products that meet the requirements of this standard should be marked with the JBT9206-1999 mark and the corresponding coating material type, manufacturer name, production batch number, and factory date.
Various types of metallographic microscopes. bZxz.net
A2 Sample preparation
JB/T 9206-1999
Appendix A
(Appendix to the standard)
Microscopic evaluation method for pore level of diffusion type hot-diffused aluminum layer A2.1 Cut the sample in a cold state by mechanical method, and its cross section should be perpendicular to the hot-diffused aluminum layer. A2.1 The sample should be inlaid or clamped with a fixture to prevent corners. A2.3 The sample should be polished after grinding.
A3 Pore level evaluation
A3.1 The pore level assessment is carried out on the polished surface of the sample. A3.2 The pore level is assessed according to Table A1 and Rating Chart A1, and is divided into six levels. A3.3 The assessment result is expressed as the maximum pore level of the sample. A3. 4 The magnification is generally 200 times. Table AI Pore level and characteristics
Maximum pore size
>0.015~0.030
>0.0300.060
≥ 0.060--0.120
Method: The elliptical pore size is determined by the average of the major and minor axes. Supplementary explanation
Unformed network
Constructed network
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