The 2020 new version of GB/T 1732 "Determination of Impact Resistance of Paint Films" has been implemented on October 1, 2021. Compared with the original 1993 version of the standard, the details of the revision have been explained in the new standard, including:
Deleted the normative references "GB 308", "GB 708", "GB 1727" and "GB 1764"; added the normative references "GB/T 308.1-2013" "GB/T 9278*" "GB/T 13452.2" "GB/T 20777" "GB/T 37356" (see Chapter 2, Chapter 2 of the 1993 edition);
Added representations of principles and results (see Chapter 3 and Chapter 8);
- Modified the regulations on the punch and steel ball of the impact Tester (see 4.1, 3.2.2 of the 1993 edition);
- Delete the correction method of the impact Tester (see 3.4 of the 1993 edition);
Modified the size of the substrate (see 6.1, 5.1 of the 1993 edition);
Modified the distance between the edge of the impact point of the test plate and the edge of the test plate and the distance between the edge of the adjacent impact point (see 7.3, 6.2 of the 1993 edition);
Added the requirements for the height interval adjustment of the weight and the lighting conditions for the observation of the results (see 7.3);
Revised the test report (see Chapter 9, Chapter 7 of the 1993 edition).
Figure 1: The real shot of the details of the impact instrument mold base
It is normal to update the normative reference documents. After all, some of the old standards cited may have expired, and it is a bit unreasonable to adopt them again. This time, the principle and result representation are added to make the standard of paint film impact more systematic. For the punch and steel ball of the impact instrument, the old version of the standard stated that it should meet the requirements of GB 308 8IV, that is, the 8mm steel ball of the G5 standard. However, the 2020 standard directly defines the diameter of the steel ball on the punch. (8.000±0.015)mm, the hardness (HRC) is 61~66, which should meet the requirements of GB/T 308.1-2013.
The relatively big change is the requirement for the impact substrate tinplate or steel plate. Taking tinplate as an example, the size of 50*120mm has not changed. What has changed is the thickness of the tinplate. The old version directly specifies 0.3mm, but it is given in the new version. A larger range (0.2~0.3mm). The thickness of the steel plate is the same as the old version, but the size has changed from 65*150mm to 70*150mm.
Another big change is the test requirements. The old version of the standard requires that the impacted edge of the test plate should not be less than 15mm, but in the new version it only requires not less than 10mm. And a step-by-step detection definition is made for the impact height and coating impact, and the height is changed by 5cm or multiples of 5cm each time, making the impact test more specific and quantifiable. The old version lacked this part. From the perspective of Beichao, this is the biggest bright spot in the new standard.
Figure 2 The real shot of the scale details of the impact meter
In general, the changes in GB/T1732-2020 are the above. For specific standards, please refer to the following link:
GB/T 1732-1993 "Determination of impact resistance of paint film"
GB/T 1732-2020 "Determination of impact resistance of paint film"
For the test and discussion on the impact of paint film, welcome to NBCHAO for exchanges!
