Basis Of working pressure Asme B16.5 1

[AliGrailly]

Hi engineers

I want to know how to obtain working pressure of flange 600# at 38 degree equal to 102.1? Material A105

Appendix B in B16.5 not clearly describe just mentioned formula that cannot achieve it also Asme Viii Appendix 2

Stress value ÷ 8750 × 600

if stress up to 40 celcius =161 mpa

161 × 145 ÷ 8750 × 600 ÷ 14.5 =110.4 bar not 102.1

 

[SnTMan]

AliGrailly, I'm working on US units here, so bear with me.

Referring to B16.5 (2003) B2.1, B2.2, B3 and Sec II, Part D (2017) I get the following:

C1 = 1.0
Pr = 600
pc = 1500

S1, from B2.2:
(a)(1) = 60% of 38 ksi = 22800 psi
(a)(2) as above, T = 100 F
(a)(3) = 1.25 * 25% of 70 ksi = 21875 psi

S1 = least of, S1 = 21875 psi

This gives pt = 21875 / 8750 * 600 = 1500 (103.4 bar)

This is equal to pc, but greater than the Table F2-1.1 rating, 1480 psi or Table 2-1.1 value 102.1 bar

I can't explain the discrepancy, but I believe your value of S1 161 Mpa / 23351 psi is too high.

Forget Apx 2, the basis between it and B16.5 are not comparable.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[AliGrailly]

Hi and thanks Friend : SnTMan


ref to table Y-1 Asme section ii part d Yield strength at temp 40 celcius for material A105 was 248mpa ~ 36000 psi

Asme B16.5 - Appendix B
B2.2
a(1) 60% of the specified minimum yield strength at38°C (100°F)


248×145.0377×60%÷8,750×600~1480 psi
1480÷14.5~102.1 Pr

As you told before 1.25×25%×70000÷8750×600=1500 Pc

Pr<=Pc

Now in table Y-1 Tensile str for A105 At Temp 40(c) is 248 and at temp 65 (c)= 233 how to obtain Yield Str at temp 50(c)?

 

[SnTMan]

AliGrailly, well I see I have performed some "sloppy work". Specified Minimum Yield Strength of SA-105 is indeed 36 ksi at 100F, as shown in both Table 1A and Table Y-1

This makes S1 = 21600, and pt = 1481 psi / 102.1 bar.


Thanks for the catch

Now in table Y-1 Tensile str for A105 At Temp 40(c) is 248 and at temp 65 (c)= 233 how to obtain Yield Str at temp 50(c)?

Intermediate values may be found by any rational interpolation scheme.

The problem with sloppy work is that the supply FAR EXCEEDS the demand