Welcome

Sunday, June 17, 2012

NUT Factor / Slip Factor


Dear readers, in continuation with my previous post, Let us discuss about the Coefficient of friction

The basic formula T = K x D x P stated earlier takes these factors into account and provides users with a starting point for establishing an initial target tightening torque. The K factor in this formula is always an estimate. That is the coefficient of friction, frequently referred to as the "Nut factor." / “Slip Factor “


The value of this factor indicates that harder, smoother, and/or slicker bolting surfaces, such as threads and bearing surfaces, require less rotational force (torque) to stretch (tension) a bolt than do softer, rougher, and stickier surfaces
If Surface is not treated Slip factor is 0.20
If Surface is blasted, any loose rust removed, no pitting than Slip factor is 0.50
If Surface is blasted and hot tip galvanised than Slip factor is 0.10
If Surface is blasted and painted than slip factor is 0.30
The most commonly used bolting K factors arc 0.20 for plain finished bolts, 0.22 for zinc plated bolts, and 0.10 for waxed or highly lubricated bolts.
For More details about Torque Click Torque
For More Details of Torque Calculation Click Tor-Cal



Best Quote."Planning without action is futile. Action without planning is fatal". Have a Nice Day

Sunday, June 10, 2012

Bolt Torque Calculations

Dear readers in continuation with my previous post, Let us discuss about the “What torque should be given for the Bolts?”
The only way to properly determine the optimum tightening torque for a given application is to simulate the exact application. This should be done with a tension indicating device like Torque Wrench or Spanner. The widely recognized engineering formula is T= K x D x P

T=Target tighten torque
K= Coefficient of friction (nut factor / Slip Factor), always an estimation in this formula
D = Bolts nominal diameter
P = Clamp Load or Bolt's desired tensile load (generally 75% of yield strength)

Above Three factors affect how much tension occurs when a given amount of tightening torque is applied. The first factor is the bolt's diameter. Naturally M24 bolts take more force to tighten than M16 bolt. The second factor is the bolt's grade. It takes more force to stretch a 10.9 Grade bolt than it does to stretch an 8.8 Grade bolt because of the greater material strength. The third factor is the coefficient of friction often called as nut factor and it is always estimation.
Keep in mind this is only an estimated value. It may provide satisfactory performance, but it also may not. It is extremely important to realize that this tightening value is valid only so long as all of the aspects of the application remain constant. Don’t think if you are giving more torque means it is good for structure / application, because during the torque operation bolt will be stretched. If more stretched than required it may be broken. So each and every application should be evaluated on its own to determine the optimum torque value for each application. If you are not aware please refer the manufacturer recommendations & Technical specification or use above formula with contingency.
Co-Efficient of Friction / Slip factor or Nut Factor details will be followed my Next Post.

For More details about Torque Click Torque
Best Quote :"Never leave that till tomorrow which you can do today". Have a Nice Day
Related Posts Plugin for WordPress, Blogger...

Labels

Abbreviations (27) ABW (1) AC (2) Acre (2) Admixture (3) Alloy Steel (1) Analysis (1) ANSI (1) Anti friction bearing (2) Apothecaries Mass (1) Arc welding (1) Avoirdupois Mass (1) AWG (4) AWS (4) BCR 295 (2) Beam (22) Bearings (5) Blasting & Painting (8) Blogoversary (4) Bolt (8) CAR A/C (1) Cartoon (2) Cement (1) Cent (2) CHANNEL (8) Chequered Plate (1) Chinese (4) Civil (7) Classification (3) Cleaning (4) Cold Rolled Steel (2) Colour Code (1) Column Section (1) Computer (1) Concrete (4) Construction Industry (11) Conversion Table (4) Cooking (1) Crane Rail (2) Cylinders (1) Density (1) DFT (2) Drill bit (1) Drill gauge (1) Drilling (1) Dry Ice (1) EHS (1) Electrical (1) Electrode (1) Ellipcon Steel (1) Elliptical Hollow Section (1) EN 10083-3 (1) EN 10219 (1) Engineer Day (7) Engineering Miracle (2) Environment (1) Equipment (2) ESI (1) European Steel (3) Factory Act (1) fasteners (1) Fibre Rope (4) Fire (1) FLAT (3) floating crane (1) Flood (1) Foil (1) Formula (1) FRP (2) GAUGE (9) General (32) Greetings (9) H-beam (4) Handrail (1) Heavy Weight Beam (1) HeliArc (1) Helmet (2) HEXAGOAN (2) Hollow Rectangle (3) Hollow Square (5) Hollow Steel (10) Hot rolled Steel (30) HR & IR (2) HSFG (1) HSS (9) HT BOLT (1) I-Beam (4) Information (8) Informations (4) Introduce (4) IP (1) IPE (3) IS 1173 (5) IS 1363 (2) IS 1786 (1) IS 3443 (2) IS 4923 (2) IS 808 (15) IS:1732 (1) ISA (2) ISCR (1) ISHB (3) ISJB (4) ISJC (2) ISLB (3) ISLC (2) ISMB (4) ISMC (2) ISMCP (1) ISNT (2) ISSC (2) ISWB (3) JIS G3466 (1) Joints (1) Junior Beam (2) Junior Channel (3) Labour Law (5) Labour Welfare (3) Lamination (1) Land Measurement (2) Light Beam (2) Light Channel (3) LPG Cylinder (1) Man Day (1) Man Hour (1) Man Month (1) Mass (3) Measurement (3) mechanical (1) Metals (7) Mile Stone (2) Music Wire (4) MWG (6) Non-Metal (2) Numbers (3) OCTOGAN (1) Oil (1) Painting (6) Parallel Flange Channel (2) PFC (2) PIPE (4) Piping (4) Planning (2) Plastics (2) Plates (1) Pole (1) PPE (1) Precautions (3) Protection (1) Rain (1) Rebar (1) Reconciliation (2) Reinforcement Rod (1) Reinforcemnt Steel (1) Reo (1) Rigging (9) River on River (1) Rope (7) ROUND (2) RSJ (1) Safety (14) Scale (1) Self Explanatory (5) SEP (5) Serrated Flat (1) Sheet (3) Short cut key (1) Sling (1) Slit Tee (1) Specific Gravity (4) Spoon (1) SQUARE (2) SSPC (1) Steel (21) Steel Beam (7) Steel Section (6) Steel Section Type (5) Stick welding (1) Structural Steel (58) Surface Preparation (8) SWG (5) SWL (1) Technical (9) Tee Section (5) Thanks (7) TIG (1) TIG Welding (1) Tips (2) Tools & Tackles (2) Torque (6) Troy Mass (1) TUBE (2) Turnbuckle (1) UB (2) UC (2) Unit of Mass (1) UNIT WEIGHT (57) Universal Beam (1) universal Column (2) Useful Tips (2) Valve (1) Water (4) Weather (1) Weight (14) Welding (12) Wide Flange Beam (2) Wind (7) Wind Speed (4) Wire Rope (3) Wishes (19) WWD (1)

Contact Form

Name

Email *

Message *

Note

1) I have extracted the information from reference sources which may not be in accordance with the latest Standards - as identified.

2) The data’s are based on a review of various reference sources. For important work please check against quality information sources.

3) The Articles are no way connected to company of author belongs.

4) This Blog will not be liable for any, direct or indirect, consequential or incidental damages or loss arising out of the use of this information.

5) If you have any suggestions or feedback on how this blog can improve it for you, please feel free to e-mail me (engineerdiary@gmail.com) Self will try my best to keep up with it!

6) Paypal account of this site is engineerdiary@gmail.com

7) If your brand/company is keen to work with Engineer Diary for advertisement and sponsorship, you can drop us an email at engineerdiary@gmail.com

8) For More Disclaimer please refer Disclaimer Page