SAEJ400測試標書
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Copyright ©2002 Society of Automotive Engineers, Inc.
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SURFACE
VEHICLE
400 Commonwealth Drive, Warrendale, PA 15096-0001
RECOMMENDED
PRACTICE
J400
REV.
NOV2002
Issued 1968-07
Revised 2002-11
Superseding J400 DEC2001
Test for Chip Resistance of Surface Coatings
1. Scope—This SAE Recommended Practice covers a laboratory procedure for testing and evaluating the
resistance of surface coating to chipping by gravel impact. The test is designed to reproduce the effect of
gravel or other media striking exposed paint or coated surfaces of an automobile and has been correlated with
actual field results. The specific intent of the test is to evaluate organic surface coatings or systems on flat test
panels; however, It may be possible to extend this type of testing to finished parts or other types of materials
such as anodized aluminum or plated plastics if the results are interpreted with respect to the limitations and
intent implied by the original testing procedures and rating system.
This document may involve hazardous materials, operations, and equipment. This document does not purport
to address all of the safety problems associated with its use. It is the responsibility of whoever uses this
document to consult and establish safety and health practices and determine the applicability of regulatory
limitations prior to use.
All dimensions are nominal unless otherwise noted.
2. Reference
2.1 Related Publication—The following publication is provided for information purposes only and is not a
required part of this document.
2.1.1 GENERAL MOTORS PUBLICATION—Available from GM AC Rochester/GMC, P.O. 1360, Flint, MI 48501-8054.
GMR-767—The Measurements of Chipping
3. Summary of Method—The test consists of projecting standardized road gravel by means of a controlled air
blast onto a suitable test panel. The testing apparatus is called a gravelometer, designed to contain road
gravel, a test panel holder, and a gravel projecting mechanism. The projecting mechanism, located in front of
the test panel, consists of an air nozzle in the base of an inverted pipe tee. The stem of the pipe tee points
upward and is located beneath a vibrating hopper into which the gravel is poured. The gravel, falling into the
air blast, is projected toward and impacts upon the test panel, which is usually held perpendicular to the
impinging gravel. All testing is conducted under controlled temperature conditions, generally room
temperature (ambient) or –29 °C ± 3 °C (–20 °F ± 5 °F). After the gravel impact, tape is applied to remove any
loose paint chips remaining on the panel, and the degree of chipping is determined by visual comparison with
the SAE Chipping Rating Standards1, by counting the number and sizes of all chips, or by other methods
deemed suitable between the contractual parties involved.