1、EFFECTS OF HIGH TEMPERATURES AND FIT-UP OF RIVETED JOINTSON STEEL RIVETSSTP-PT-086STP-PT-086 Effects of High Temperatures and Fit-up of Riveted Joints on Steel Rivets Prepared by: Linn Moedinger Strasburg Railroad Company George W Galanes, P.E. Diamond Technical Services, Inc. Date of Issuance: Octo
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9、he publisher. ASME Standards Technology, LLC Two Park Avenue, New York, NY 10016-5990 ISBN No. 978-0-7918-7194-2 Copyright 2017 by ASME Standards Technology, LLC All Rights Reserved STP-PT-086: Effects of High Temperatures and Fit-up of Riveted Joints on Steel Rivets iii TABLE OF CONTENTS Foreword i
10、v Summary . v 1 Introduction 1 2 Background 2 3 Rivet Test Procedure 3 4 Metallurgical Evaluation of Steel Rivets 4 5 Conclusions 8 References . 9 APPENDIX A: List of Metallurgical Testing Performed 10 APPENDIX B: Macroetched rivet head to shank transitions 11 APPENDIX C: SGS MSi Test Results 15 APP
11、ENDIX D: Micrographs of Hot Driven Rivet Microstructures 18 LIST OF FIGURES Figure 4-1: Copy of the Material Test Report for the rivet material used in this project. 4 Figure 4-2: The hot driven steel rivets after extraction from the steel test plates. . 5 Figure 4-3: Head and shank for rivet 1A2 11
12、 Figure 4-4: Head and shank for rivet 1B2 11 Figure 4-5: Head and shank for rivet 2A1 . 12 Figure 4-6: Head and shank for rivet 2B1 12 Figure 4-7: Head and shank for rivet 3A2 . 13 Figure 4-8: Head and shank for rivet 3B2 13 Figure 4-9: Head and shank for rivet 3C2 14 Figure 4-10: Micrograph showing
13、 the microstructure of the un-driven steel rivet. . 7 Figure 4-11: Rivet 1A2 microstructure driven at 2250 degrees F (1230 degrees C) immediately into holes 1/8 inch (3.2 mm) oversized 18 Figure 4-12: Rivet 1B2 microstructure driven at 1950 degrees F (1065 degrees C) immediately into holes 1/8 inch
14、(3.2 mm) oversized 18 Figure 4-13: Rivet 2A1 microstructure driven at 2250 degrees F (1230 degrees C) immediately into holes 1/16 inch (1.6 mm) oversized. . 19 Figure 4-14: Rivet 2B1 microstructure driven at 1950 degrees F (1065 degrees C) immediately into holes 1/16 inch (1.6 mm) oversized 19 Figur
15、e 4-15: Rivet 3A2 microstructure driven at 2250 degrees F (1230 degrees C) immediately into holes 1/16 inch (1.6 mm) oversized, tight plates 20 Figure 4-16: Rivet 3B2 microstructure driven at 2250 degrees F (1230 degrees C) immediately into holes 1/16 inch (1.6 mm) oversized, tight plates 20 Figure
16、4-17: Rivet 3C2 microstructure driven at 2250 degrees F (1230 degrees C) immediately into holes 1/16 inch (1.6 mm) oversized, tight plates 21 LIST OF TABLES Table 1-1: Spreadsheet showing the battery of metallurgical tests for the rivets. 10 Table 4-1: SGS MSi Tensile Test Results 16 Table 4-2: Perc
17、entage Change in Tensile Properties in Comparison with Un-driven Rivet Steel.17 Table 4-3: SGS MSi Hardness Test Results.18 STP-PT-086: Effects of High Temperatures and Fit-up of Riveted Joints on Steel Rivets iv FOREWORD The purpose of this project is to evaluate the effects of driving temperature
18、and fit-up on steel rivets used in boiler construction. There has been conflicting information as to the maximum driving temperature for hot riveting of steel rivets used in boiler construction. Strasburg Railroad Company was the project coordinator and provided a series of hot driven rivets after r
19、eceiving funding from ASME-ST-LLC. Strasburg contracted the metallurgical testing of the rivets to Diamond Technical Services, Inc. Both Strasburg Railroad Company and Diamond Technical Services, Inc. would like to acknowledge ASME for funding this entire project. Established in 1880, the ASME is a
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22、LLCs mission includes meeting the needs of industry and government by providing new standards-related products and services, which advance the application of emerging and newly commercialized science and technology, and providing the research and technology development needed to establish and mainta
23、in the technical relevance of codes and standards. Visit http:/asmestllc.org/ for more information. STP-PT-086: Effects of High Temperatures and Fit-up of Riveted Joints on Steel Rivets v SUMMARY This study evaluated the maximum hot rivet driving temperature, and the effects of plate fit-up, rivet h
24、ole clearances and joint tightness on rivet steel properties. The most urgent need was to establish whether heating rivets to 2250 degrees F (1230 degrees C) for driving had a detrimental effect on final steel rivet properties compared with steel rivets heated at 1950 degrees F (1065 degrees C). The
25、 1950 degrees F (1065 degrees C) maximum rivet driving temperature was evaluated in a previous, privately funded study, however the scope of that study was focused only on temperature. This study focused on the two temperatures previously mentioned, but added additional physical properties to the te
26、st plates for consideration outside recommended parameters for standard hot riveting. These anomalies included oversizing rivet holes, poor plate fit-up with springback, and soaking rivets at the higher temperatures 1950 degrees F and 2250 degrees F (1065 degrees C and 1230 degrees C) for extended p
27、eriods (10 minutes and 20 minutes) before driving into the test plates. The steel rivets for this project were supplied from ASTM A675 carbon steel bar, 7/8-inch diameter. A pneumatic hammer was used to drive the 7/8-inch (22-millimeter (mm) diameter rivets into button head style heads after heating
28、 to the designated metal temperature for hot forming. Heating of rivets was performed using electric resistance heating and a gas fired furnace. Three test conditions were performed. Under the first test condition, carbon steel test plates were prepared with rivet holes 1/8-inch (3.2 mm) oversized,
29、to see if the additional upsetting of the rivet to fill the larger holes was detrimental to the finished product. The second test condition used carbon steel test plates with holes 1/16-inch (1.6 mm) oversize (normal) to simulate the situation where plates are not tightly fit together, thus allowing
30、 the plates to spring-back during hot riveting. This test was in response to a specific report in an early study that indicated this cyclic compression/stretch during driving created a sub-par finished rivet. The third test condition dealt with carbon steel test plates with 1/16-inch (1.6 mm) oversi
31、zed holes that were tightly held together. In addition, during this third series of tests, the rivets were held for 10 minutes and 20 minutes at metal temperature before driving. Each rivet was carefully extracted from the carbon steel test plates with the material subjected to the following metallu
32、rgical lab tests; macro-photographs of extracted rivets, tensile testing using sub-size tensile specimens, hardness testing, and metallographic examination. The results of this study revealed the maximum driving temperature can remain at 2250 degrees F (1230 degrees C) under the 2017-edition of the
33、ASME Boiler and Pressure Code (BPVC), Section I, Part PL. Metallurgical testing concluded that the rivets after hot driving increased in strength with slightly increased ductility. The increase in ultimate tensile strength and yield strength most likely occurred from two metallurgical factors; the f
34、irst was dynamic recrystallization during hot riveting and transformation products which formed in the rivet steel microstructure upon cooling. Overall, the effects of oversized plate holes, plate tightness and extended soak time (20 minutes) did little to change the result of increased tensile prop
35、erties and improved ductility for the hot driven rivets. The rivets driven at 1950 degrees F (1065 degrees C) or 2250 degrees F (1230 degrees C) into oversized holes, with plate spring back and a soak time of up to 20 minutes before hot riveting showed no detrimental phases or anomalies. STP-PT-086:
36、 Effects of High Temperatures and Fit-up of Riveted Joints on Steel Rivets 1 1 INTRODUCTION The objective of this study was to evaluate the effects on rivet properties based on maximum hot rivet driving temperatures, plate fit-up, rivet-hole clearances and joint tightness. The most urgent need was t
37、o establish whether heating rivets to 2250 degrees F (1230 degrees C) for driving had a detrimental effect on final rivet mechanical properties compared with rivets heated at 1950 degrees F (1065 degrees C). At present, the 2017 Edition of the BPVC, Section I (1) has limited the maximum temperature
38、for hot riveting to 2250 degrees F (1230 degrees C). However, this maximum driving temperature has been challenged by others in the past who have maintained the maximum temperature should be 1950 degrees F (1065 degrees C). This study focused on the two temperatures previously mentioned, but added a
39、dditional variables to the test plates for consideration outside recommended parameters for standard hot riveting practices. These variables included oversizing rivet holes, poor plate fit-up using spring back, and soaking rivets at the higher temperatures 1950 degrees C and 2250 degrees F (1065 deg
40、rees C and 1230 degrees C) for extended periods (10 minutes and 20 minutes) before driving into the test plates. To accomplish the objective, it was decided to simulate riveting of locomotive boilers by using carbon steel test plates 4-inches (102 mm) by 20-inches (508 mm) by -inch (19 mm) in thickn
41、ess with pre-drilled holes to accommodate carbon steel rivets. The rivets for this entire project were supplied from ASTM 675 carbon steel bar, 7/8-inch in diameter. A pneumatic hammer was used to drive the 7/8-inch (22 mm) diameter rivets into button head style heads after heating to the designated
42、 metal temperature for hot forming. Heating of rivets was performed using electric resistance heating and a gas fired furnace. Three test conditions were performed; The first test condition used carbon steel test plates which were prepared with rivet holes 1/8-inch (3.2 mm) oversized, to see if the
43、additional upsetting of the rivet to fill the larger holes was detrimental to the finished steel rivet mechanical properties. The second test condition used carbon steel test plates with holes 1/16-inch (1.6 mm) oversized (normal) to simulate the situation where plates are not tightly fit together,
44、thus allowing the plates to spring-back during hot riveting. This test was in response to a specific report in an early study that indicated this cyclic compression/stretch during driving created a sub-par finished rivet. The third test condition dealt with carbon steel test plates with 1/16-inch (1
45、.6 mm) oversized holes that were tightly held together. In addition, during this third series of tests, the rivets were held for 10 minutes and 20 minutes at metal temperature before driving. A complete spreadsheet summarizing the metallurgical lab tests is shown in Table 1-1 in Appendix A. A fourth
46、 test had been in the original test program where hand riveting is accomplished using hand hammers with no pneumatic or hydraulic assistance. While this may be done on a very limited basis for historical purposes, the scope of its use in Test 4 did not seem relevant enough to justify the expenditure
47、 given limited budget constraints. Upon completion of riveting by Strasburg Railroad, the hot riveted carbon steel test plates were sent to a metallurgical lab under the direction of DTS Metallurgical. Each rivet was carefully extracted from the carbon steel test plates with the material subjected t
48、o the following metallurgical lab tests; macro-photographs of extracted rivets, tensile testing using sub-size tensile specimens, hardness testing, and metallographic examination. STP-PT-086: Effects of High Temperatures and Fit-up of Riveted Joints on Steel Rivets 2 2 BACKGROUND Over the years when
49、 hot riveting was the primary method used in joining plates and support structures for locomotive boilers, many different practices were employed and in later years, various studies were conducted to determine the effects on the end product. Additionally, with the decline of riveting in mainstream boiler manufacturing, there has been considerable “technological whisper down the lane”. In both cases, previous studies and urban myths tended to contradict one another. A literature review revealed several interesting te
