GB/T 4297-2004 Macrostructure test method for wrought magnesium alloys
Some standard content:
ICS 77. 120. 20
National Standard of the People's Republic of China
GB/T 4297-2004
Replaces GB/T4297—1984
Inspection method for macrostructure of wrought magnesium alloy products2004-04-30Promulgated
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of ChinaStandardization Administration of the People's Republic of China
Implemented on 2004-10-01
GB/T4297—2004
This standard is a revision of GB/T 4297-1984 & Inspection method for macrostructure of wrought magnesium alloy products. Compared with GB/T4297—1984, this standard has the following major changes: This standard adds the inspection method and standard pictures for defects of magnesium alloy ingots. This standard amends the original standard particle size measurement formula from 0.67g to 0.5g. This standard is proposed by China Nonferrous Metals Industry Association. This standard is under the jurisdiction of the National Technical Committee for Standardization of Nonferrous Metals. This standard was initiated by China Northeast Light Alloy Co., Ltd. and drafted by the South China Product Quality Supervision and Inspection Center of China Nonferrous Jinli Industry. The main drafters of this standard are Hou Yi, Wang Meiqi, Shi Ci, Zhang Ming, and Shuai Liwei. This standard is interpreted by the National Technical Committee for Standardization of Nonferrous Metals. The previous versions of the standards replaced by this standard are: GB/T4297-1984.
1 Scope
Macrostructure inspection method for wrought magnesium alloys
GB/T4297-2004
This standard specifies the preparation, etching and structure inspection methods, defect classification, test report, etc. of specimens for macrostructure inspection of wrought magnesium alloys.
This standard applies to the macroscopic and fracture microstructure inspection of wrought magnesium alloy cast chains and processed products. 2 Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties who reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, its latest version applies to this standard. GB/T3246.2—2000 Macroscopic microstructure inspection method for wrought aluminum and aluminum alloy products 3 Sample preparation
3.1 Sampling
3.1.1 Round ingot sample: After cutting off the specified length of the head and tail, cut along the transverse direction of both ends, with a thickness of 25mm±5mm. 3.1.2 Samples for extruded products: Cut horizontally at the end of the extrusion, with a thickness of 30 mm ± 5 mm. For special products, cut according to the requirements of the drawings. 3.1.3 Samples for forgings (free parts, die forgings): Cut according to the requirements of the technical drawings. 3.1.4 For the fracture inspection samples of extruded products, the samples after low-power microstructure inspection can be used. The fracture samples of forgings are cut according to the requirements of the technical drawings.
Sample,
Support seat,
.Workbench.
a) Fracture
3.2 Sample processing
Figure 1 Fracture test schematic
b) Tearing
3.2.1 The inspection surface of all low-power samples needs to be milled. Its roughness (R.) should not be less than 3.2m. Other processing methods may also be used under the premise of ensuring that the inspection quality is not reduced. 3.2.2 The fracture specimen should be slotted at the receiving part. The specimens with too small size and strange shape should be cut into molds, but the mold depth should not exceed 1/3 of the thickness. If the specimen is large, it is not necessary to slot it. 3.2.3 The fracture specimen is broken or split on the press (or by other methods) for the first time, as shown in Figure 1. 3.2.4 The surface of the milled specimen and the fracture after breaking or tearing should be kept clean and not contaminated or damaged. 3. 3 Sample oil
3. 3. 1 Reagents
3. 3. 1. 1
3. 3. 1. 2
3. 3. 1. 3
3. 3. 1. 4
3. 3. 1. 5
3. 3. 1. 6
3. 3. 1. 7
3. 3. 1. 8
Hydrochloric acid (p1. 19 g/mL)
Sulfuric acid (p1. 84 g/ml.)
Citric acid;
Ethanol solution of picric acid (60 g/L);
Acetic acid (pl. 049 g/ml)+
casein anhydride;
hydrofluoric acid (p115g/mL)
3. 3. 2 Diffuser
The composition and use of the diffusant are shown in Table 1.
Citric acid
Citric acid
Piracic acid acetyl ester solution
1000mL
100 mL
1 000 ml.
Note: Other etchants can also be used without reducing the amount of the two. 3. 3. 3 Polishing agent
The composition and use of the polishing agent are shown in Table 2.
Sodium nitrate
Hydrogen phosphate
For etching of magnesium alloy castings
For etching of dry magnesium alloy products
For etching of iron-magnesium alloy products
For light cleaning of samples after etching with No. 1 or No. 2 etchants in Table 1For light cleaning of samples after etching with No. 1 etchants in Table 13.3.4 Etching
GB/T 4297—2004
3.3.4.1 Place the sample with the test surface facing up in the etchant, and gently shake it. Etching for 0.5min~3min. Then rinse it in running water, then put it in the light cleaning agent for light cleaning, and finally rinse it with running water. 3.3.4.2 Magnesium alloys are easily oxidized and contaminated. They should be rinsed after etching. If contamination occurs, they should be etched again to achieve bright and clean results. 4 Organization inspection
4.1 General principles
Inspect according to the quality requirements specified in the relevant technical standards and technical agreements, and change the direction of light illumination at any time, and observe each part in detail. When encountering suspicious places that are difficult to identify with flesh, use a magnifying glass of 10 times or less to inspect, or conduct fracture and star emblem organization and other segment analysis as appropriate.
4. 2 Grain size inspection
4.2.1 Evaluate according to the grain size classification standard of CB/T3246.2. 4.2.2 When measuring the grain size, the average grain area (or diameter) or the number of grains per unit area should be used. The measurement steps are as follows. 4.2.2.1 According to the size of the grain, draw a 10mm×10mm or 50mm×50mm square on the sample, or draw a circle with a diameter of 10 mm or 50 mm.
4.2.2.2 Find out the number of complete grains in the square or circle and the number of grains cut around the square or circle, calculate the total number of grains according to formula (1) and formula (2), and calculate the average area of the grains according to formula (3). When g is an even number = +0.5g
When g is an odd number = +0.5(g+1)
: In the formula:
Total number of grains in a square or circle;
Number of grains that are completely cut in a square circle:
Number of grains cut around a grid line or circle: F—Average area of grains, in square millimeters (mm\); s Area of a square or circle, in square millimeters (mm\). 4.2.2.3 At least three locations are selected for measurement on each specimen, and then the average value is taken. 4.2.2.4 When the grain sizes vary greatly and the distribution is extremely uneven, the largest grain area should be selected. 5 Slag inclusion erosion test
·5.1 The specimens that need to be inspected for flux shall be subjected to mechanical fume retrieval according to 3.2.1. (1)
5 .2 Place the processed sample in an automatic controlled spray device (vertical effect) with constant humidity (humidity ≥ 95%) and constant temperature (30℃ ± 2℃) and corrode for 8 hours.
5.3 Corrosion solution: ammonium oxalate aqueous solution (0.1R/L~1g/I.). 5.4 No water marks should be formed on the sample during the corrosion process. 5.5 If white nodules appear after corrosion and protrude from the surface, remove the nodules to expose holes, which is flux inclusion. 5.6 If it is not certain, a fluorine ion qualitative test can be carried out. Use a dropper to drop dilute nitric acid (1+1) on the defect. After 3s-5$ reaction, absorb it onto the surface and add 1~2 drops of 0.1(mol/) silver nitrate latent solution. If a white precipitate is formed, it proves to be flux inclusion. The reaction formula is:
6 Defect classification
MgCl +2AgNO,-→+2AgC1+ +Mg(NO,):6.1 Non-metal inclusions (including flux inclusions) On low-magnification specimens, this defect is a black dot or amorphous material with unclear boundaries. After processing and deformation, it extends along the metal flow direction. After etching, the surface is concave or milky holes appear. Its distribution is irregular, as shown in circle 2. The microstructure is a chaotic structure or a striated structure composed of black linear objects and blocks, as shown in Figure 3. The fracture surface shows a dark amorphous loose structure as shown in Figure 4. The flux inclusion is a dark nodule on the well-corroded specimen. After removing the nodule, the pores are revealed (see Chapter 4: Flux inclusion slag removal test), as shown in Figure 5. 6.2 Cyanide pores
On the transverse low-magnification specimen, a round or round hole with a smooth inner wall that can be seen without etching, as shown in Figure 6: After pressure processing, the pores can be deformed but cannot be pressed together. 6.3 Primary crystal segregation
On the low-magnification specimen, this defect is a protruding, sharply delineated, slightly darker than the matrix, point-like aggregate, and selective to light, as shown in Figure ?. The microstructure is composed of many granular or blocky primary crystals of intermetallic compounds aggregated together, arranged along the deformation direction after processing and deformation, as shown in Figure 8 (a, b): Sometimes coexisting with slag inclusions, as shown in Figure 8c. The fracture surface shows a small crystal group with a certain luster, as shown in Figure 9.
6.4 Manganese inclusions
On the low-magnification specimen, this defect is a silver-gray point-like aggregate protruding from the base structure, as shown in Figure 10. The fracture surface is an amorphous brown aggregate, as shown in Figure 11.
6.5 Large grains
On the low-magnification specimen, this defect is fan-shaped coarse grains, as shown in Figure 12; the fracture surface is strip-shaped or flaky, as shown in Figure 13. 6.6 Shrinkage
In the strong deformation zone of the outer layer of the transverse specimen of the extruded product, there are kitchen-shaped circles or multi-layer rings, protruding from the surface, serious blackening or cracking, which is called shrinkage, as shown in Figure 14. If it is not protruding or the surface is concave, and the continuity of the corrosion is not destroyed, it is called annular stripes, as shown in Figure 15.
6.7 Formation
On the edge of the transverse specimen of the extruded product, there are arc-shaped or broken lines, protruding from the surface or cracking, which is called stratification, as shown in Figure 16. 6.8 Coarse ring
On the transverse specimen of the extruded product, coarse recrystallized grain structure appears along the periphery, which is called coarse ring, as shown in Figure 17: 6.9 Bright ring
On the edge of the transverse specimen of the extruded product, a ring-shaped bright band appears, which is called bright ring, as shown in Figure 18. The microstructure observation shows that the bright band is fine recrystallized grains. If there is no fright phenomenon, it is not considered a defect. If there is cracking, it is treated as layering. 6.10 Extrusion crack
On the edge of the transverse specimen of the extruded product, an arc-shaped crack appears, as shown in Figure 19: On the longitudinal surface, it is periodic cracking, and the severe one is serrated.
6.11 Fold
On the edge of the low-magnification specimen of the forging, a smooth crease line extending from the outside to the outside appears, which is called fold, as shown in Figure 20. The new fold is generally accompanied by irregular flow lines.
6.12 Lamellar fracture
Layered structure appears after the specimen is broken, which is called lamellar fracture, as shown in Figure 21. 6.13 Flow pattern irregularity
On the low-magnification specimen made by die forging, the metal flow lines are not distributed according to the outline of the workpiece, which is called flow pattern irregularity, as shown in Figure 22a. If the flow line passes through the workpiece specimen, it is called through flow, as shown in Figure 22i. 7 Test report
The test report should include the following:
a) History of the specimen:
b) Sampling location:
Alloy grade or chemical composition;
Processing status:
Defect type;bZxz.net
Texture description;
Magnification and etching conditions.
）ZK61M cast chain 111
b) ME20M thick plate 3:2
Figure 2 Low-power structure of non-metallic inclusions
1 diffuse etchant diffuses
Figure 3 Microstructure of non-metallic inclusions
1 diffuse etchant diffuses
GB/T 4297--2004
GB/T4297—2004
）ZK61M ingot 11
b) ME20M thick plate 1+ 1
c)AZ40M bar 11
Fig.4 Non-metal inclusion fracture structure
）1:1
h)Forging 1
Fig.5 Flux inclusion slag macrostructure
No.1 etchant etch
Fig.6 Porosity
No.1 etchant etch 1:1
GB/T 4297-2004
GB/T4297—2004
ZK61M cast chain 111
h)ZKS1M die forging 1
cF AZ4IM profile
Figure 7 Primary crystal segregation macrostructure
No. 1 etchant diffuse etching
a) A241M material X200 not etched
hZK61M die sensitive parts X200 not properly etched
Crystal segregation and Keqing coexist 200 not etched
Figure 8 Primary product segregation microstructure
GB/T4297—2004
GB/T 4297—2004
a) ZK61M ammonium casting 1:1
b) AZ40M bar 1:1
AZ41M profile 1:1
Figure 9 Primary crystal segregation fracture structure
) ZK6IM die forging 1:113 Flow irregularity
On the low-magnification specimen of die forging, the metal flow lines are not distributed according to the contour of the workpiece, which is called flow irregularity, as shown in Figure 22a. If the flow line passes through the section of the workpiece specimen, it is called through flow, as shown in Figure 22i. 7 Test report
The test report should include the following:
a) History of the specimen:
b) Sampling location:
Alloy grade or chemical composition;
Processing status:
Defect type;
Texture description;
Magnification and etching conditions.
）ZK61M cast chain 111
b) ME20M thick plate 3:2
Figure 2 Low-power structure of non-metallic inclusions
1 diffuse etchant diffuses
Figure 3 Microstructure of non-metallic inclusions
1 diffuse etchant diffuses
GB/T 4297--2004
GB/T4297—2004
）ZK61M ingot 11
b) ME20M thick plate 1+ 1
c)AZ40M bar 11
Fig.4 Non-metal inclusion fracture structure
）1:1
h)Forging 1
Fig.5 Flux inclusion slag macrostructure
No.1 etchant etch
Fig.6 Porosity
No.1 etchant etch 1:1
GB/T 4297-2004
GB/T4297—2004
ZK61M cast chain 111
h)ZKS1M die forging 1
cF AZ4IM profile
Figure 7 Primary crystal segregation macrostructure
No. 1 etchant diffuse etching
a) A241M material X200 not etched
hZK61M die sensitive parts X200 not properly etched
Crystal segregation and Keqing coexist 200 not etched
Figure 8 Primary product segregation microstructure
GB/T4297—2004
GB/T 4297—2004
a) ZK61M ammonium casting 1:1
b) AZ40M bar 1:1
AZ41M profile 1:1
Figure 9 Primary crystal segregation fracture structure
) ZK6IM die forging 1:113 Flow irregularity
On the low-magnification specimen of die forging, the metal flow lines are not distributed according to the contour of the workpiece, which is called flow irregularity, as shown in Figure 22a. If the flow line passes through the section of the workpiece specimen, it is called through flow, as shown in Figure 22i. 7 Test report
The test report should include the following:
a) History of the specimen:
b) Sampling location:
Alloy grade or chemical composition;
Processing status:
Defect type;
Texture description;
Magnification and etching conditions.
）ZK61M cast chain 111
b) ME20M thick plate 3:2
Figure 2 Low-power structure of non-metallic inclusions
1 diffuse etchant diffuses
Figure 3 Microstructure of non-metallic inclusions
1 diffuse etchant diffuses
GB/T 4297--2004
GB/T4297—2004
）ZK61M ingot 11
b) ME20M thick plate 1+ 1
c)AZ40M bar 11
Fig.4 Non-metal inclusion fracture structure
）1:1
h)Forging 1
Fig.5 Flux inclusion slag macrostructure
No.1 etchant etch
Fig.6 Porosity
No.1 etchant etch 1:1
GB/T 4297-2004
GB/T4297—2004
ZK61M cast chain 111
h)ZKS1M die forging 1
cF AZ4IM profile
Figure 7 Primary crystal segregation macrostructure
No. 1 etchant diffuse etching
a) A241M material X200 not etched
hZK61M die sensitive parts X200 not properly etched
Crystal segregation and Keqing coexist 200 not etched
Figure 8 Primary product segregation microstructure
GB/T4297—2004
GB/T 4297—2004
a) ZK61M ammonium casting 1:1
b) AZ40M bar 1:1
AZ41M profile 1:1
Figure 9 Primary crystal segregation fracture structure
) ZK6IM die forging 1:1
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.