This standard specifies the test method and evaluation method for the impact resistance of furniture surface paint films. This standard is applicable to the evaluation of the impact resistance of furniture wood surface paint films. GB/T 4893.9-1992 Determination of impact resistance of furniture surface paint films GB/T4893.9-1992 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of impact resistance of furniture surface paint film
Furniture-Test for surfacesAssessment of resistance to impactSubject content and scope of application
This standard specifies the test method and assessment method for the impact resistance of furniture surface paint film. This standard is applicable to the assessment of the impact resistance of furniture wood surface paint film. 2 Reference Standards
GB308 Rolling Bearing Steel Ball
3 Principle
GB/T 4893.9-92
A steel cylindrical impact block falls from a specified height along a vertical guide tube and impacts a steel ball with a specified diameter and hardness placed on the surface of the specimen. According to the degree of damage to the paint film at the impacted part of the specimen surface, the impact resistance of the paint film is evaluated with a digital grade. 4 Test Equipment
4.1 Impactor
4.1.1 Horizontal Base
The horizontal base is a rigid base for placing the specimen, and its plane size is at least 200mm×250mm. 4.1.2 Vertical Guide Tube
The inner diameter of the vertical guide tube is 40±5mm, and a disc with a thickness of 10±0.5mm is installed at the bottom. A hole for placing the steel ball is opened in the center of the disc, and the diameter of the hole is 14:mm (see Figure 1). 4.1.3 Impact block
The impact block is made of alloy steel with a hardness slightly lower than that of the steel ball, and its mass is 500±5g (see Figure 1). The outer diameter of the impact block is about 1mm smaller than the inner diameter of the vertical guide tube.
4.1.4 Steel ball
The outer diameter of the steel ball is $14-0.01mm, and its hardness is 60～66HRC (see Figure 1). Other requirements shall comply with GB308 regulations. 4.2 Magnifying glass
The magnification of the magnifying glass is 10 times.
4.3 Light source
60W incandescent frosted lamp.
Approved by the State Administration of Technical Supervision on June 2, 1992, and implemented on January 1, 1993
5 Impact height and its selection
5.1 Impact height
Impact block
Horizontal base
GB/T4893.9
Figure 1 Impactor
Vertical guide tube
The impact heights are: 10, 25, 50, 100, 200400mm. The impact height is the distance from the upper surface of the steel ball to the bottom end face of the impact block, and its measurement deviation is ±0.5mm.
5.2 Selection of impact height
When determining whether the impact resistance of the paint film meets the specified requirements, it can be directly carried out according to a corresponding impact height. When determining the maximum impact resistance of the paint film, each impact height should be passed step by step until the maximum impact height or the paint film shows the fifth level of damage.
6 Test pieces
6.1 Classification of test pieces
Test pieces can be painted with samples of certain specifications; or they can be directly made of finished furniture or a part of furniture. 6.2 Preparation of test pieces
The test piece should be flat. The size of the painted sample is 200mm×180mm. The materials and surface finishing processes used to prepare the test piece must be the same as those of the finished furniture. After the test piece is made, it should be placed in an environment with air circulation at a temperature not lower than 15℃ for 28 days. Before the test, the test piece should be placed in the environment specified in Chapter 7 for 7 days. 6.3 Determination of the impact position of the test piece
The center of each impact position should be no less than 50mm from the edge of the test piece, and the distance between the centers of each impact position should be no less than 20mm. The center position of the impact position should be determined by drawing a grid. The size of the grid is shown in Figure 2. If the surface substrate of the test piece has a structural texture, the long side of the test piece should be along the direction of its texture.
GB/T4893.9-92
When testing finished furniture or a part of furniture, a test part with good rigidity should be selected. 5×20(~100)
7Test environment
20(min)
Direction of grain
Figure 2 Determination of the impact part of the test piece
The entire test should be carried out in an environment with a temperature of 20±2℃ and a relative humidity of 60% to 70%. 8Test steps
8.1 Placement of test piece
Put the test piece flat on a horizontal base so that all impact parts are within the range of the horizontal base. (08)0×
When the test piece is a finished furniture or a part of furniture, it should be placed on a horizontal rigid base (usually on a cement floor). 8.2 Impact test
Place the impactor on the specimen so that the steel ball is at the center of the impact part, then lift the impact block to the specified impact height and impact the steel ball once. Impact 5 parts at each impact height. After each test, check whether the steel ball is deformed. If obvious deformation is found, it should be replaced. 8.3 Inspection of impact parts
Place the specimen under the light source and use a magnifying glass to check the degree of damage of each impact part. When checking, you can use methods such as shaking the specimen, light source or changing the observation angle. If necessary, you can also apply a water-based colorant with a large contrast to the color of the surface paint film on the impact part. After a while, wipe off the residual colorant on the surface of the specimen and then check again. 9 Result evaluation
The evaluation of the impact part is shown in Table 1 and Figure 3. 593
GB/T 4893. 9-92
No visible change (no damage)
No cracks on the paint film surface, but visible impact marksThe paint film surface has slight cracks, usually 1 to 2 ring cracks or arc cracksThe paint film surface has moderate to heavy cracks, usually 3 to 4 ring cracks or arc cracksThe paint film surface has serious damage, usually more than 5 ring cracks, arc cracks or paint film peelingFigure 3 Visible changes
When evaluating the results, first evaluate the numerical grade of each impact part of the same impact height, and then take the nearest integer to the arithmetic mean as the final evaluation result.
Example 1: Evaluation grade 2,2,2,3,3;
Final evaluation result: 2.
Example 2 Assessment level: 2, 2, 3, 3, 3;
Final assessment result: 3.
The final assessment result shall be given for each selected impact height test. If necessary, the diameter of the impression at the impact site can be measured and recorded at the same time. For the relevant measurement method, see Appendix A (Supplement). The test result of each impact site shall be jointly assessed by three inspectors. 10 Test report
The test report shall at least include the following contents: a.
The substrate, coating name and brief coating process of the test piece; the selected impact height;
The assessment level of each impact site and the final assessment result of the selected impact height; d.
GB/T 4893.9-92bZxz.net
Any discrepancy with the provisions of this standard; indicate the name and number of this standard adopted; test unit and date.
GB/T4893.9—92
Appendix A
Measuring method for the diameter of the mark on the impact part of the paint film on the furniture surface (supplement)
This appendix specifies the measuring method and calculation method for the diameter of the mark on the impact part of the paint film on the furniture surface. A1 Instruments and materials
A1.1 Vernier caliper with an accuracy of 0.02mm. A1.2 Double-sided blue carbon paper.
A1.3 Copy paper with a quantitative value of 17±1.0g/m2. A2 Test method
Put the double-sided blue carbon paper and copy paper flat on the surface of the test piece in turn, and then put the impactor that meets the requirements of Article 4.1 on the copy paper, so that the impact block impacts the steel ball once according to the specified impact height, and impacts 5 parts at each impact height. After the test, use a vernier caliper to measure the maximum mark diameter left on the copy paper, and keep one decimal place for the effective value. A3 Calculation method
The arithmetic mean of the diameters of the five impact marks at the same impact height can be calculated according to formula (A1): Zd
Wherein: a—the average diameter of the five impact marks at the same impact height; d:——the diameter of the ith impact mark at the same impact height. Additional remarks:
This standard was proposed by the Ministry of Light Industry of the People's Republic of China. This standard is under the jurisdiction of the National Furniture Standardization Center. This standard was drafted by the Shanghai Furniture Research Institute. The main drafters of this standard are Ding Zhaoxin and Zhang Jiaji. 596
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