LOCTITE WEBINAR SERIES Threadlocking & the Torque …henkeladhesivesna.com/knowledge-center/wp-content/uploads/2017/0… · How does a nut & bolt work? ... • Clamp load is the force

LOCTITE WEBINAR SERIES

Threadlocking & the

Torque-Tension Relationship

2

Market Development Director

[email protected]

Meet Your Presenters

Doug Lescarbeau

Application Engineer

[email protected]

Michael Feeney

June 24, 2016 LOCTITE WEBINAR SERIES LOCTITE Instant Adhesives

3

Agenda

LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension RelationshipJune 24, 2016

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 Threadlockers Effect

8. Questions

4

Agenda


1. Who is Henkel?







9. Questions

8. Equipment Solutions & Additional Resources

5 June 24, 2016 LOCTITE WEBINAR SERIES Threadlocking & the Torque-Tension Relationship

Who we areGlobal leading positions in consumer and industrial businesses

Adhesive TechnologiesLaundry & Home Care Beauty Care

Industrial BusinessConsumer Businesses


Who we areHenkel at a glance 2014

Almost

50,000employees worldwide

43%of our sales generated

in emerging markets

2.9 bnadjusted1 operating

profit (EBIT)

61%of our sales generated

by our top 10 brands

139 yearsof brand success

Around

18.1 bnsales,

+3.0% organic

sales growth

1 Adjusted for one-time charges/gains and restructuring charges.


Adhesive Technologies Business Units

Business Units

General Industry

Packaging & Consumer Goods

Automotive & Metals

Aerospace

Electronics

Consumer & Craftsmen

Top Brands


Adhesive TechnologiesLeading solution provider in adhesives, sealants & functional coatings

Customer Partnership Innovation Leader

Deep industry expertise

Leading brands for industrial customersand 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)

9

Agenda


1. Who is Henkel?







9. Questions



Threaded Assemblies How does a nut & bolt work?

Application of on-torque Clamp load is retained by

Bolt is stretched like a spring

Target clamp load is reached

a) Bolt head friction

b) Thread friction


Threaded AssembliesWhat is clamp load?

CLAMP LOAD

FASTENER

ELONGATION

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

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!

12

Agenda


1. Who is Henkel?







9. Questions



Threaded AssembliesWhy do threaded assemblies fail?


Threaded AssembliesThread friction in detail

metal to metal

air


Threaded AssembliesReasons for failure

Self-looseningRelaxation

Corrosion Different thermal expansion

Steel

Copper


Threaded AssembliesShortcomings 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


Threaded AssembliesKey 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


Threaded AssembliesRoot 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.


Threaded AssembliesClamp 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.


Threaded AssembliesWhat is the target for clamp load?

PROOF LOAD

Elastic

Stretch

Cla

mp

Fo

rce

YIELD STRENGTH

Ultimate Tensile Strength

Permanent Stretch0

100% PROOF (90% YIELD)

75% PROOF

50% PROOF

Target

How much tension do you need on a bolt?

Typically the target is 75% of the proof load


Threaded AssembliesTarget 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.


Threaded AssembliesTorque 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.


Torque-Tension RelationshipTorque Charts

Size Clamp Load lbs. Plain Plated

1/4-20 (0.250) 2,850 12 ft. lbs. 9 ft. lbs.

5/6-18 (0.3125) 4,725 25 ft. lbs. 18 ft. lbs.

3/8-16 (0.375) 6,975 44 ft. lbs. 33 ft. lbs.

7/16-14 (0.4375) 9,600 70 ft. lbs. 52 ft. lbs.

1/2-13 (0.500) 12,750 106 ft. lbs. 80 ft. lbs.

9/16-12 (0.5625) 16,350 153 ft. lbs. 115 ft. lbs.

5/8-11 (0.625) 20,325 212 ft. lbs. 159 ft. lbs.

3/4-10 (0.750) 30,075 376 ft. lbs. 282 ft. lbs.

7/8-9 (0.875) 41,550 606 ft. lbs. 454 ft. lbs.

1-8 (1.000) 54,525 909 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. 1.363 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.

Tightening Torque Guide

SAE Grade 8 Coarse Thread

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Agenda


1. Who is Henkel?







9. Questions



Threaded Assemblies Clamp LoadFriction

1 UNC Unified National Coarse2 UNF Unified National Fine

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)

UNC1 UNF2

Bolt Tension 15% 10%

Thread Friction 39% 42%

Head Friction 46% 48%

Total 100% 100%


Threaded Assemblies Clamp LoadFriction

Which factors affect the friction of a threaded assembly?

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.

27

Agenda


1. Who is Henkel?







9. Questions



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.



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.



Bolt system placed in

Skidmore-Wilhelm clamp

load tester.

Pressure measured and

directly correlated by

knowledge of the

diameter of the piston to

measure the clamp load.

Skidmore-Wilhelm

Bolt Tester



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%).

Average Clamp Loads for Various Bolt Manufacturers

0

2000

4000

6000

8000

10000

12000

A B C D E

Cla

mp

Lo

ad

(lb

s)

Bolt Manufacturers

Dry

21% range



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.


0

2000

4000

6000

8000

10000

12000

A B C D E

Cla

mp

Lo

ad

(lb

s)

Bolt Manufacturers

Dry

Loctite 243

12% range



Liquid threadlockerreduced variability by

providing a constant

lubricity.

Some variance remains, which is

normal.


0

2000

4000

6000

8000

10000

12000

A B C D E

Cla

mp

Lo

ad

(lb

s)

Bolt Manufacturers

Dry

Loctite 243

12% range

34

Agenda


1. Who is Henkel?







9. Questions



Threaded Assemblies Clamp LoadTorque-Tension Relationship

The long form equation used to describe the relationship between torque and tension

ISO 10647

The short form equation: T = K x F x D


Threaded Assembly Clamp LoadTorque-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 (Nm, lbin, lbft)

K = Torque Coefficient or K Factor

F = Clamp Load (N, lb)

D = Nominal Diameter (mm, in)


Threaded Assembly Clamp LoadTorque-Tension Relationship K factor

Does a threadlocker have a constant 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.

The K factor describes the friction of an assembly, not a lubricant

Threadlocking is one variable


Threaded Assemblies Clamp LoadHow 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

Piston

Pressure Gauge

(Calibrated to read force)

Pressurized Fluid

Cylinder


Threaded AssembliesFriction

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.

40

Agenda


1. Who is Henkel?






9. Questions




Torque-TensionLubricity Benchmarking

0

0.1

0.2

0.3

0.4

No lubricant (Dry) Motor Oil Lithium Grease Loctite Moly Paste Loctite 243 Loctite 2047

K F

acto

r

Thread Lubricants

50% Proof Load 75% Proof Load 90% Proof Load

K Factor of Various Thread Lubricants


Threaded Assembly Clamp LoadConsistent Assemblies

Why does this happen?

Scatter without LOCTITE

Scatter with LOCTITE

Torque

Tension


Threaded Assembly GallingLubrication 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

Aluminum 136

Brass 69

Zinc 67

Steel 32

Stainless Steel 8Most likely to gall

Least likely to gall

44

Agenda


1. Who is Henkel?







9. Questions


45

AG Equipment Total Solutions

Equipment.loctite.com

Lig

ht

Cu

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So

luti

on

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Dis

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Sys

tem

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C

on

tro

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Dis

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alv

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Mo

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Han

d-H

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D

isp

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sin

gC

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su

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s

June 24, 2016

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Equipment SelectionCriteria checklist

What are the considerations when choosing

appropriate equipment?

Adhesive chemistry? Adhesive package? 1-part or 2-part adhesive? Adhesive pot life / work life? Viscosity of adhesive? Dispense pattern? Curing requirements? Size / configuration of customer parts? Production rate? Low level detection? External interface? Capital budget?

June 24, 2016

47

AG 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.

1-800-LOCTITE Equipment.services

@Henkel.com

Equipment Sourcebook

June 24, 2016

48

Henkel Adhesive Resources

www.Loctite-success.com na.henkel-adhesives.com/oem The Adhesive Sourcebook Plastic, Rubber and Metal Bonding Guides Application assistance

1-800-LOCTITE (562-8483) 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

June 24, 2016

http://www.loctite-success.com/http://na.henkel-adhesives.com/oem

49

www.Loctite-success.comGeneral Intro to the Advantages of Adhesives

June 24, 2016

Customer Success Stories &

Videos

Solutions Guide

Adhesive Testing Lab

Information & Videos

Information on Additional

Webinars

Contact Us

http://www.loctite-success.com/

50

na.henkel-adhesives.com/oemNA General Manufacturing Site Advanced Information

June 24, 2016

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

http://na.henkel-adhesives.com/oem

51

Why Henkel?Adhesive supplier considerations

June 24, 2016

Breadth & depth of product offering

Technical service / support

Quality standards / industry certifications

Testing capabilities

Global reach and resources

Process knowledge / dispensing equipment

Industry expertise / innovativeness

Overall value of offering

52

Agenda


1. Who is Henkel?







9. Questions



Questions

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. 2016 Henkel Corporation.

All rights reserved.

Documents

LOCTITE WEBINAR SERIES Threadlocking & the Torque …henkeladhesivesna.com/knowledge-center/wp-content/uploads/2017/0… · How does a nut & bolt work? ... • Clamp load is the force