Comments on: Calculating Yield and Tensile Strength

By: Dane McKinnon

Dane McKinnon — Tue, 29 Jan 2013 15:08:42 +0000

@Ted – The error you are making is a common one. When calculating the strength of a fastener, the tensile stress area you use is the area of the minor(root) diameter of the threads, in this case 5/8-11 is 0.226 sq in. So 36,000 x 0.226= 8,136lbs. If instead, you are trying to calculate the strength of a full sized bar with no threads, then you did the math correctly.

By: Ted

Ted — Tue, 29 Jan 2013 14:42:24 +0000

Ted again
I did make a mistake but the question is the same.
.312 x.312 x 3.14 = .305 x 36,000psi =11,003
Thanks Ted

By: Ted

Ted — Tue, 29 Jan 2013 12:49:17 +0000

I am trying to calculate the yield strength of that 5/8″ bolt and I’m not seeing how you are doing your math. If I take the area (pie x r sqd) I get 3.14 x .312 x.312 =1.962 x 36,000psi tensile = 70,650 yield. what am I doing wrong?
Thanks Ted

By: Ed Easter

Ed Easter — Tue, 04 Dec 2012 00:21:30 +0000

Frequently people are concerned about threads pulling through the nut (shearing the threads). If nut and bolt are made from the same material,and thread engagement is at least 55% the bolt will pull into (tensil) before the thread shears.(General Electric standard 12A1200),
Tensil strength of any material is available in many metalurgical sites on the internet. You only need to calculate the cross section area of the bolt X tensil strength of material bolt is made of. That will tell you how many bolts are needed to support the load + safety factor

By: Dane McKinnon

Dane McKinnon — Tue, 13 Nov 2012 20:31:30 +0000

@Pierce – Ryan’s question was answered by us directly above his question. I would agree with that response – it isn’t anything we can easily calculate.

By: Pierce

Pierce — Tue, 13 Nov 2012 20:21:10 +0000

Id be interested in the same thing that Ryan is asking above. Any thoughts? Thanks, Pierce from PBEMusic

By: Dane McKinnon

Dane McKinnon — Mon, 24 Sep 2012 14:59:04 +0000

@Ravish – Yes it is possible, but not common, that a bolt can pass the tensile test but fail the proof load test. Typically speaking, the 0.2% offset is only used when testing for yield strength, not for testing proof stress. Proof stress is a simple pass or fail test where the full size bolt is tensioned to a predetermined proofload value, held for 10 seconds, then measured to see if it elongated. Yield strength differs in that the bolt or test coupon is pulled to failure, and the yield is calculated (using the 0.2% offset method) along with the tensile, elongation and reduction of area. In order to calculate using the 0.2% offset method, you must first secure data from which a stress-strain diagram may be drawn. More detailed information can be found by looking at ASTM F606 Section 3.6.3.1 or by contacting an accredited test lab.

By: Ravish

Ravish — Mon, 24 Sep 2012 11:34:52 +0000

how do you calculate 0.02% Proof stress. is it possible that your bolt passes in tensile strength and fails in proof stress.

By: W J

W J — Fri, 22 Jun 2012 01:13:11 +0000

Example 1: Area of rectangular cross section
width (w) = 0.505 in.
thickness (t) = 0.5 in.
Area (a) = W x T
AREA (A) = 1.5 X 0.5
AREA (A) = 0.75

LOAD =12500 LBS
AREA = 0.2 IN. 2
Tensile = 12500 x 5
tensile = 62500
Must be an easier way of computing this Tensile Stength of Steel in question.
most of the time I deal with ASTM OR API CODES
SUCH AS X70 OR X65 FOR USE IN THE GAS AND OIL PIPELINE.

;

By: Dane McKinnon

Dane McKinnon — Tue, 21 Feb 2012 19:48:12 +0000

@Donald E Brundage – I would try to contact the International Code Council or look on their website; they write a lot of the specifications for expansion anchors and those types of construction products. http://www.iccsafe.org/Pages/default.aspx