Chimical Composition

[sowhatso]

I am working in a water project, at which welded steel pipes will be used according to the following standard:

ASTM A53, Grade B, Type (E), and rated for 600 psi working pressure.

The contractor proposed to supply the steel pipes from one of the manufacture, the submitted datasheets from the manufacturer confirm that the pipes will be supplied according to the subject standard and withstand 600psi working pressure. BUT, the submitted datasheets showing the chemical composition different than ASTM A53 Gr.B, my concern is about the carbon content and the manganese. The contractor submitted datasheets show the chemical composition as follow:

Carbon: 0.12 min , 0.17 max , and .15 aim
Manganese: .85 min, 1.1 max, 0.95 aim
P: 0.02 Max , S: 0.01 Max , Si:0.2 , Cu: 0.15 max, Ni:0.1,Cr:.07,Mo:0.03,AL:0.035,Sn:.02,Cb:0.008,Ca:.005.

However ASTM A53,Gr B, have different percentages of content : Carbon: 0.3 & Manganese: 1.2. In addition, the other difference in the alloy content.
I know that carbon content is important commercial steel alloy. And Increasing carbon content increases hardness and strength and improves harden ability. And also when these steels are designed for welded applications, others said that for welded steel pipe steel having good wear resistance properties the low alloy steel having good wear resistance properties comprising, by weight, 0.2 to 0.6 percent carbons and 0.1 to 3.0 percent manganese as basic components

I need to know if the manufacturer content of carbon and manganese is acceptable or not as I am not sure if ASTM call for exact content or the maximum content should not be more than what they specified. What make me confused is that ASTM A53 grade A call for 0.25 carbon content and grade B call for 0.3 carbon content which mean that the main difference is carbon content, and the contractor datasheets show 0.12 carbon content … so what do you think …

 

[nhliew]

sowhatso,

My copy of ASTM A53 shows grade B composition to be:
Carbon 0.30% max, Manganese 1.20 max%.

To answer your question, ASTM specs do not call for exact composition, but specify a range. As long as your pipe chemical composition remain within the specs, they are considered as compliant.

 

[sowhatso]

nhliew ,

Thanks for your input , but the Carbon content they chose is less than Grade A , and we apesify grade B , so can we get the required tensile strength and yield strenght for grade B ( 35000 psi and 60000 psi ) with the same carbon content the manufacturer proposed ?

This raise the issue of how can we get grade B strength with low carbon content ??

 

[unclesyd]

What is the TS and YS of the pip listed on your data sheet?

Does the data sheet list a primary manufacturer of the material?

 

[sowhatso]

The manufacturer datasheets show the following :

minimum yield strength 35 ksi
maximum yield strength 60 ksi

The submitted minimum yied strength match the ASTM A53 Gr.B ( Table 2 - Tensile requirements ) , but they did not show the minimum tensile strength that should be 60 ksi min , they only talked about the yield strength min/max , is it enough to depend on the yield strength data ?? or they have also to submit the tensile strength data ??

 

[unclesyd]

The data sheet you receive should be equivalent to a Mill Test Report used in the US. The reported chemical composition and physical tests should be results from the actual material used in manufacture of the pipe. It should have specific values for each batch (heat) of metal.

It sounds like the supplier is given typical or book values for the material properties expected for SA53 grade pipe.

The chemistry vales are usually all within the specification unless an exception has been granted, while the physical values TS and YS are a little higher than the minimums.

 

[SJones]

Precisely! If you don't specify requirements for inspection documents, you get 'typicals'. Always try to select and specify the appropriate documentation requirements from either ISO 10474 or EN 10204. This will then govern what gets specifically tested and what results get reported.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[sowhatso]

I just need to know one thing ... during the facbrication of steel , what is the main difference between grade A and grade B ,I know the strength is different between both,, BUT is it related to the content or the heat treatment ?? I thought the carbon content is one of the main issue .

What is the main difference in facbrication between Grade B and Grade A ?