LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

Transcription

1 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

2 Meet Your Presenters Doug Lescarbeau Michael Feeney Market Development Director m Application Engineer 2 August 11, 2017 LOCTITE WEBINAR SERIES LOCTITE Instant Adhesives

3 Agenda 1. Who is Henkel? 2. Mechanics of a Threaded Assembly 3. Threaded Assembly Failures 4. Friction in a Threaded Assembly 5. Fastener Variability Study 6. The Torque-Tension Relationship 7. A Threadlocker s Effect 8. Questions 3 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

4 Agenda 1. Who is Henkel? 2. Mechanics of a Threaded Assembly 3. Threaded Assembly Failures 4. Friction in a Threaded Assembly 5. Fastener Variability Study 6. The Torque-Tension Relationship 7. A Threadlocker s Effect 8. Equipment Solutions & Additional Resources 9. Questions 4 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

5 Who we are Global leading positions in consumer & industrial businesses Adhesive Technologies Beauty Care Laundry & Home Care 5 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship August 11, 2017

6 Who we are Henkel at a glance 2016 More than 50,000 employees worldwide from 123 nations 42% of our sales generated in emerging markets Around 18.7 bn sales, +3.1% organic sales growth 171 manufacturing and 22 major R&D sites around the world 3.2 bn adjusted 1 operating profit (EBIT) 1 Adjusted for one-time charges/gains and restructuring charges. More than 140 years of success 6 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

7 Adhesive Technologies Leading solution provider in adhesives, sealants & functional coatings Customer Partnership Innovation Leader Deep industry expertise Leading brands for industrial customers and consumers Best-in-class quality and service Global presence and customer proximity Comprehensive portfolio of leading technologies Innovation driver in the industry Shaping industry megatrends (e.g. sustainability, lightweight) 7 8/11/17 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

8 Agenda 1. Who is Henkel? 2. Mechanics of a Threaded Assembly 3. Threaded Assembly Failures 4. Friction in a Threaded Assembly 5. Fastener Variability Study 6. The Torque-Tension Relationship 7. A Threadlocker s Effect 8. Equipment Solutions & Additional Resources 9. Questions 8 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

9 Threaded Assemblies How does a nut & bolt work? Application of on-torque Bolt is stretched like a spring Target clamp load is reached Clamp load is retained by a) Bolt head friction b) Thread friction 9 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

10 Threaded Assemblies What is clamp load? Clamp load is the force that holds a joint together In a threaded assembly, the clamp load is equal in magnitude to the tension of the bolt but opposite in direction CLAMP LOAD FASTENER ELONGATION Why is it important? A bolted joint is designed so that the external forces never overcome the clamp load. This is why fasteners are used! 10 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

11 Agenda 1. Who is Henkel? 2. Mechanics of a Threaded Assembly 3. Threaded Assembly Failures 4. Friction in a Threaded Assembly 5. Fastener Variability Study 6. The Torque-Tension Relationship 7. A Threadlocker s Effect 8. Equipment Solutions & Additional Resources 9. Questions 11 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

12 Threaded Assemblies Why do threaded assemblies fail? 12 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

13 Threaded Assemblies Thread friction in detail air metal to metal 13 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

14 Threaded Assemblies Reasons for failure Relaxation Self-loosening Different thermal expansion Corrosion Steel Copper 14 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

15 Threaded Assemblies Shortcomings of mechanical locking devices Loosen under vibration, thermal expansion and/or improper torque Do not seal threads Require extensive inventory of several shapes and sizes Prone to rust More costly than Loctite threadlockers 15 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

16 Threaded Assemblies Key characteristics of a Loctite threadlocker Single component Fills all voids to unitize the nut and bolt Cures to thermoset plastic Creates material closure Maintains friction by adhesion Resists vibration 16 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

17 Threaded Assemblies Root Cause Analysis Root cause analysis often does not go far enough, often stopping when a bolt has failed. Failure can be either broken or yielded, or when clamp load is lost. Why do bolts break? Typically because clamp load is lost, bolts become loose, and then they get sheared. Need to go further and understand the mechanics of the bolted joint. This will lead to true root cause analysis, the failure being a vibrational locking system was not employed, or not enough clamp load was delivered. 17 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

18 Threaded Assemblies Clamp Load = Bolt Tension Another mode of failure of a bolt is lack of adequate clamp load on assembly. Many variables are involved in what clamp load delivers. Lubricity is key to assembly, but not everything. 18 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

19 Threaded Assemblies What is the target for clamp load? How much tension do you need on a bolt? Typically the target is 75% of the proof load Target Ultimate Tensile Strength Clamp Force YIELD STRENGTH PROOF LOAD 100% PROOF (90% YIELD) 75% PROOF 50% PROOF 0 Elastic Stretch Permanent Stretch 19 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

20 Threaded Assemblies Target for clamp load? Methods to precisely determine the correct bolt stretch Micrometer on a bolt to directly measure bolt stretch. Good for critical applications such as wind tower bases, but is a slow and delicate process. Torque to yield bolts used in the automotive cylinder head assembly. Creates an even clamp load by permanently stretching; clamp load a function of the steel metallurgy. Downside is bolts are single-use only. The most common method remains a torque wrench. 20 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

21 Threaded Assemblies Torque Tension Relationship How is the tension achieved? Torque is applied to the nut or head of the bolt. How much torque should be applied? Dry or wet (oiled) torque values are specified by the bolt manufacturer or a torque chart. What if you use a threadlocker? Does this change the torque value? Yes, applying a threadlocker changes the friction and, therefore, changes how much torque becomes clamping force. Does every threadlocker have the same effect on torque? No, there are differences in their ability to lubricate. 21 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

22 Torque-Tension Relationship Torque Charts Tightening Torque Guide SAE Grade 8 Coarse Thread Size Clamp Load lbs. Plain Plated 1/4-20 (0.250) 2, ft. lbs. 9 ft. lbs. 5/6-18 (0.3125) 4, ft. lbs. 18 ft. lbs. 3/8-16 (0.375) 6, ft. lbs. 33 ft. lbs. 7/16-14 (0.4375) 9, ft. lbs. 52 ft. lbs. 1/2-13 (0.500) 12, ft. lbs. 80 ft. lbs. 9/16-12 (0.5625) 16, ft. lbs. 115 ft. lbs. 5/8-11 (0.625) 20, ft. lbs. 159 ft. lbs. 3/4-10 (0.750) 30, ft. lbs. 282 ft. lbs. 7/8-9 (0.875) 41, ft. lbs. 454 ft. lbs. 1-8 (1.000) 54, ft. lbs. 382 ft. lbs. 1-1/8-7 (1.125) 68,700 1,288 ft. lbs. 966 ft. lbs. 1-1/4-7 (1.250) 87,225 1,817 ft. lbs ft. lbs. 1-3/8-6 (1.375) 103,950 2,382 ft. lbs. 1,787 ft. lbs. 1-1/2-6 (1.500) 126,450 3,161 ft. lbs. 2,371 ft. lbs. 22 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

23 Agenda 1. Who is Henkel? 2. Mechanics of a Threaded Assembly 3. Threaded Assembly Failures 4. Friction in a Threaded Assembly 5. Fastener Variability Study 6. The Torque-Tension Relationship 7. A Threadlocker s Effect 8. Equipment Solutions & Additional Resources 9. Questions 23 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

24 Threaded Assemblies Clamp Load Friction Approximately 85-90% of the effort used to tighten a threaded fastener is lost to friction Only about 10-15% of the effort is used to generate clamp load Torque Absorption in a Tightened Bolt (Percent of Tightening Torque) UNC 1 UNF 2 Bolt Tension 15% 10% Thread Friction 39% 42% Head Friction 46% 48% Total 100% 100% 1 UNC Unified National Coarse 2 UNF Unified National Fine 24 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

25 Threaded Assemblies Clamp Load Friction Lubricants Diameter of the bolt Substrate Thread pitch & fit Length of engagement Speed of assembly Surface finish Presence or absence of washer Torquing nut vs. torquing of head Hole clearance Etc. Which factors affect the friction of a threaded assembly? 25 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

26 Agenda 1. Who is Henkel? 2. Mechanics of a Threaded Assembly 3. Threaded Assembly Failures 4. Friction in a Threaded Assembly 5. Fastener Variability Study 6. The Torque-Tension Relationship 7. A Threadlocker s Effect 8. Equipment Solutions & Additional Resources 9. Questions 26 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

27 Fastener Variability Study Experiment to verify if surface finish and under-head bolt design would produce a variance in torque Industrial distributors indicated that zinc plated steel was the most commonly supplied bolt material. As the zinc coating prevents rust, no oil film was observed. 27 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

28 Fastener Variability Study 5/8 -NC Grade 5 Zinc plated bolts and nuts from five different bolt manufacturers. Bolts were assembled with a calibrated torque wrench to 112 foot-pounds (152 Nm), the standard SAE Grade 5 recommendations for steel bolts. 28 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

29 Fastener Variability Study Bolt system placed in Skidmore-Wilhelm clamp load tester. Skidmore-Wilhelm Bolt Tester Pressure measured and directly correlated by knowledge of the diameter of the piston to measure the clamp load. 29 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

30 Fastener Variability Study First study tested bolts in as-received condition to illustrate the variance in clamp load. Table 1 shows it produced a clamp load range of 4,100 lbs. (21%). Clamp Load (lbs) Average Clamp Loads for Various Bolt Manufacturers 21% range Dry 0 A B C D E Bolt Manufacturers 30 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

31 Fastener Variability Study In second study, same bolts from five manufacturers Using a chemical threadlocker Range dropped from 4,100 to 1,300 pounds of clamp load difference with chemical threadlocker. Clamp Load (lbs) Average Clamp Loads for Various Bolt Manufacturers 12% range Dry Loctite 243 A B C D E Bolt Manufacturers 31 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

32 Fastener Variability Study Liquid threadlocker reduced variability by providing a constant lubricity. Average Clamp Loads for Various Bolt Manufacturers % range Some variance remains, which is normal. Clamp Load (lbs) Dry Loctite A B C D E Bolt Manufacturers 32 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

33 Agenda 1. Who is Henkel? 2. Mechanics of a Threaded Assembly 3. Threaded Assembly Failures 4. Friction in a Threaded Assembly 5. Fastener Variability Study 6. The Torque-Tension Relationship 7. A Threadlocker s Effect 8. Equipment Solutions & Additional Resources 9. Questions 33 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

34 Threaded Assemblies Clamp Load Torque-Tension Relationship The long form equation used to describe the relationship between torque and tension ISO The short form equation: T = K x F x D 34 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

35 Threaded Assembly Clamp Load Torque-Tension Relationship K factor The K factor or torque coefficient is an empirical constant value that takes into account friction and the variable diameter under the head and in the threads where friction is acting. It is determined experimentally to describe the relationship between torque and tension. T = K x F x D T = Torque (N m, lb in, lb ft) K = Torque Coefficient or K Factor F = Clamp Load (N, lb) D = Nominal Diameter (mm, in) 35 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

36 Threaded Assembly Clamp Load Torque-Tension Relationship K factor No Lubricants Diameter of the bolt Substrate Thread pitch & fit Length of engagement Speed of assembly Surface finish Presence or absence of washer Torquing nut vs. torquing of head Hole clearance Etc. Does a threadlocker have a constant K factor? Threadlocking is one variable The K factor describes the friction of an assembly, not a lubricant 36 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

37 Threaded Assemblies Clamp Load How do you test for the K factor? Assembly is loaded into unit Torque is applied to the bolt and measured Clamp load achieved from applied torque is recorded Skidmore-Whilhelm bolt tester Pressure Gauge (Calibrated to read force) Pressurized Fluid Cylinder Piston 37 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

38 Threaded Assemblies Friction Bolts received from a manufacturer may have permanent coating or plating, residual cutting fluids, anti-corrosion oils, etc. The challenge is that these are not documented, and often overlooked as to their influence on the bolted joint. The presence or absence of a lubricant will greatly change the friction coefficient by lubricating the joint. Friction can be controlled using lubricants. 38 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

39 Agenda 1. Who is Henkel? 2. Mechanics of a Threaded Assembly 3. Threaded Assembly Failures 4. Friction in a Threaded Assembly 5. Fastener Variability Study 6. The Torque-Tension Relationship 7. A Threadlocker s Effect 8. Equipment Solutions & Additional Resources 9. Questions 39 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

40 Torque-Tension Lubricity Benchmarking K Factor of Various Thread Lubricants K Factor No lubricant (Dry) Motor Oil Lithium Grease Loctite Moly Paste Loctite 243 Loctite 2047 Thread Lubricants 50% Proof Load 75% Proof Load 90% Proof Load 40 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

41 Threaded Assembly Clamp Load Consistent Assemblies Torque Scatter without LOCTITE Scatter with LOCTITE Tension Why does this happen? 41 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

42 Threaded Assembly Galling Lubrication prevents galling Galling: Wear caused by friction and the buildup of heat between two sliding surfaces. Thermal Conductivity of Metals (Btu/hr-ft-F) Copper 231 Least likely to gall Aluminum 136 Brass 69 Zinc 67 Steel 32 Stainless Steel 8 Most likely to gall 42 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

43 Agenda 1. Who is Henkel? 2. Mechanics of a Threaded Assembly 3. Threaded Assembly Failures 4. Friction in a Threaded Assembly 5. Fastener Variability Study 6. The Torque-Tension Relationship 7. A Threadlocker s Effect 8. Equipment Solutions & Additional Resources 9. Questions 43 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

44 na.henkel-adhesives.com/oem NA General Manufacturing Site In-depth Information The Adhesive Sourcebook Product Categories Market Segments Equipment Website Plastic, Rubber and Metal Bonding Guides Product Search TDS, MSDS & RoHS Buy Now How-to videos Literature, Case Histories, Quality Certifications & Additional Resources OEM Blog 44 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

45 Equipment Resources Equipment Website equipment.loctite.com Technical Repository E-Commerce Product Information Equipment Services rental/ loaners, spare parts, calibrations, repairs, warranty and technical support, etc LOCTITE Equipment Sourcebook Light Cure Solutions Dispense Valves Motion Control Dispense Systems and Controllers Consumables Hand-Held Dispensing 45 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

46 General Intro to the Advantages of Adhesives Customer Success Stories & Videos Solutions Guide Adhesive Testing Lab Information & Videos Information on Additional Webinars Contact Us 46 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

47 Henkel Adhesive Resources na.henkel-adhesives.com/oem The Adhesive Sourcebook Plastic, Rubber and Metal Bonding Guides Application assistance LOCTITE ( ) Over-the-phone assistance Technical Information Services team 8 a.m.-5 p.m. Eastern time In-person assistance Local Adhesive & Sealant Specialists Technical Customer Service department Testing services Process development Authorized Loctite Industrial Products Distributors ~ 5,000 branches in USA 47 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

48 Agenda 1. Who is Henkel? 2. Mechanics of a Threaded Assembly 3. Threaded Assembly Failures 4. Friction in a Threaded Assembly 5. Fastener Variability Study 6. The Torque-Tension Relationship 7. A Threadlocker s Effect 8. Equipment Solutions & Additional Resources 9. Questions 48 August 11, 2017 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

49 Thank You! All marks used are trademarks and/or registered trademarks of Henkel and its affiliates in the U.S. and elsewhere. = registered in the U.S. Patent and Trademark Office Henkel Corporation. All rights reserved.