1、 Grain Flow Pattern for Bolts, Screws, and StudsSAE/USCAR-8 Revision 3 December 2013 ISBN: 978-0-7680-8115-2 _ The research data, analysis, conclusion, opinions and other contents of this document are solely the product of the authors. Neither the SAE International (SAE) nor the United States Counci
2、l for Automotive Research (USCAR) certifies the compliance of any products with the requirements of nor makes any representations as to the accuracy of the contents of this document nor to its applicability for purpose. It is the sole responsibility of the user of this document to determine whether
3、or not it is applicable for their purposes. Copyright 2013 USCAR Printed in U.S.A. All rights reserved. QUESTIONS REGARDING THIS DOCUMENT: (248) 273-2470 FAX (248) 273-2494 TO PLACE A DOCUMENT ORDER: (724) 776-4970 FAX (724) 776-0790 SUMMARY OF CONTENTS 1. SCOPE 2 2. TEST PROCEDURE 2 3. GRAIN FLOW P
4、ATTERN REQUIREMENTS 2 4. REVERIFICATION . 2 5. REFERENCES 2 6. KEY WORDS . 2 SAE/USCAR-8 REVISION 3 Issued 1998-12 Revised 2013-12 Grain Flow Pattern for Bolts, Screws, and Studs SAE/USCAR-8 REVISION 3 Revised 2013-12 GRAIN FLOW PATTERN FOR BOLTS, SCREWS, AND STUDS - 2 - 1. SCOPE: This specification
5、 covers the grain flow pattern requirements in headed bolts, screws, and studs. The heading practice in the manufacture of the bolt, screw, or stud sets the grain flow pattern, but it is also greatly influenced by the fastener design. 2. TEST PROCEDURE: 2.1 Testing for grain flow shall be performed
6、after heading, prior to heat treatment, and subsequent processing of parts. After heat treatment the determination of the acceptability of grain flow is very subjective and shall not be used as primary manufacturing inspection method. NOTE: $IWHUHWFKLQJDOLJKWUHYHDOSROLVKRQDGLDPRQG wheel has the effe
7、ct of knocking back some of the raised areas on the flow line ridges. This process improves the contrast between the darker root of the etch flow line, and the lightened or polished crests to improve evaluation. 2.2 The head and shank shall be sectioned approximately on the centerline, with the shan
8、k having a minimum length of 1.0 X the diameter of the shank. 2.3 Macroetch the sectioned head and shank sufficient to reveal the grain flow pattern, using etching practice based upon ASTM E340, and shown in the manufacturers control plan. Grain flow samples shall be viewed at sufficient magnificati
9、on to allow for adequate resolution of the grain flow lines. 2.4 The sample size and frequency for the above testing shall be identified in the manufacturers control plan. 3. GRAIN FLOW PATTERN REQUIREMENTS: 3.1 Grain flow throughout the product shall be continuous and uninterrupted except in those
10、instances where a flash trim line has been determined to be acceptable. A continuous and uninterrupted grain flow must be maintained around the fillets and radii, but may be compressed. Grain flow lines terminating in head to shank fillets, radii, or onto the shank surface are not acceptable. In ups
11、et parts, the entire material compression zone in the head shall be above the head to shank radius. Figures #1, #2 and #3 show the acceptable grain flow pattern typical in flange heads. Figures #4 and #5 show the unacceptable grain flow pattern typical in flange heads for comparison. All Figures rep
12、resent a flange headed product. However, the grain flow principles and requirements apply to all head shapes. 4. REVERIFICATION: Changes in design or processing that effect grain flow pattern require re-verification. 5. REFERENCES: ASTM E340 6. KEY WORDS: End Grain, Compression Zone, Grain Flow. SAE
13、/USCAR-8 REVISION 3 Revised 2013-12 GRAIN FLOW PATTERN FOR BOLTS, SCREWS, AND STUDS - 3 - FIGURE 1 - ACCEPTABLE GRAIN FLOW PATTERN SAE/USCAR-8 REVISION 3 Revised 2013-12 GRAIN FLOW PATTERN FOR BOLTS, SCREWS, AND STUDS - 4 - FIGURE 2 - ACCEPTABLE GRAIN FLOW PHOTOGRAPH SAE/USCAR-8 REVISION 3 Revised 2
14、013-12 GRAIN FLOW PATTERN FOR BOLTS, SCREWS, AND STUDS - 5 - FIGURE 3 MARGINALLY ACCEPTABLE GRAIN FLOW PHOTOGRAPH Marginal but acceptable SAE/USCAR-8 REVISION 3 Revised 2013-12 GRAIN FLOW PATTERN FOR BOLTS, SCREWS, AND STUDS - 6 - FIGURE 4 - UNACCEPTABLE GRAIN FLOW PATTERN SAE/USCAR-8 REVISION 3 Revised 2013-12 GRAIN FLOW PATTERN FOR BOLTS, SCREWS, AND STUDS - 7 - FIGURE 5 UNACCEPTABLE GRAIN FLOW PHOTOGRAPH
