لوله های فولاد آلیاژی A691

EFW 

16" and Over 

CM-65 carbon-molybdenum steel 

CM-70 carbon-molybdenum steel

CM-75 carbon-molybdenum steel

CMSH-70 carbon-manganese-silicon steel, normalized 

CMS-75 carbon-manganese-silicon steel

CMSH-80 carbon-manganese-silicon steel, quenched and tempered

2 1⁄2 CR 1⁄2 % chromium, 1⁄2 % molybdenum steel

1CR 1 % chromium, 1⁄2 % molybdenum steel 

11⁄4 CR 11⁄4 % chromium, 1⁄2 % molybdenum steel 

21⁄4 CR 21⁄4 % chromium, 1 % molybdenum steel

3CR 3 % chromium, 1 % molybdenum steel

5CR 5 % chromium, 1⁄2 % molybdenum steel

9CR 9 % chromium, 1 % molybdenum steel 2

9 % chromium, 1 % molybdenum, vanadium, niobiumC

Pipe Grade	ASTM Specification	Post-Weld Heat-Treat Temperature Range (Stress Relieving), °F (°C)	Normalizing  Temperature max unless otherwise noted,	Quenching  Temperature max unless otherwise noted,°F (°C)	Tempering Temperature, min, °F (°C)
CM-65	A 204/A 204M	1100 to 1200 (590 to 650)	1700 (925)	…	…
CM-70	A 204/A 204M	1100 to 1200 (590 to 650)	1700 (925)	…	…
CM-75	A 204/A 204M	1100 to 1200 (590 to 650)	1700 (925)	…	…
CMSH-70	A 537/A 537M	1100 to 1200 (590 to 650)	1700 (925)	…	…
CMS-75	A 299/A 299M	1100 to 1200 (590 to 650)	1700 (925)	…	…
CMSH-80	A 537/A 537M	1100 to 1200 (590 to 650)	A	1700( 925)	1100 to 1250 (590 to 675)
1/2CR	A 387/A 387M	1100 to 1300 (590 to 705)	1850 (1010)	1700( 925)	150 to 1375 (620to745)
1CR	A 387/A 387M	1100 to 1350 (590 to 730)	1850 (1010)	1700 (925)	150 to 1375 (620to745)
11⁄4CR	A 387/A 387M	1100 to 1375 (590 to 745)	1850 (1010)	1700 (925)	150 to 1375 (620to745)
21⁄4CR	A 387/A 387M	1200 to 1400 (650 to 760)	1850 (1010)	1700 (925)	250 to 1400(675 to760)
3CR	A 387/A 387M	1200 to 1400 (650 to 760)	1850 (1010)	1700 (925)	250 to1400 (675 to760)
5CR	A 387/A 387M	1200 to 1400 (650 to 760)	1850 (1010)	1650 (900)	1300 to1400 (705 to760)
9CR	A 387/A 387M	1325 to 1375 (715 to 745)	B	…	1325 to1375 (715 to745)
91	A 387/A 387M	1350 to 1420 (730 to 770)	11900 to 2000   (1040 to 1095)	1900 min (1040 min)	1350 to 1440 (730 to 780)

In the 1999 Addenda to the 1998 Edition, ASME changed the factor of safety from 4 times to 3.5 times, increasing the allowable stress values.

factor Of Safety 3 in Asme B31.3 

در تصویر زیر حداقل استحکام کششی برای متریال A691 در جدول  ( A-1M ( Metric داده شده ،  با توجه به Grade و ملاحظه ستون ترکیب شیمیایی متفاوت است

302.3.2 Bases for Design Stresses.

d) Other Materials. Basic allowable stress values at temperature for materials other than bolting materials, cast iron, and malleable iron shall not exceed the lowest of the following:

(1) the lower of one-third of ST and one-third of tensile strength at temperature

(2) except as provided in (3) below, the lower of two-thirds of SY and two-thirds of yield strength at temperature

(3) for austenitic stainless steels and nickel alloys having similar stress–strain behavior, the lower of two- thirds of SY and 90% of yield strength at temperature [see (e) below]

(e) Application Limits. Application of stress values determined in accordance with para. 302.3.2(d)(3) is not recommended for flanged joints and other components in which slight deformation can cause leakage or mal- function. [These values are shown in italics or boldface in Table A-1, as explained in Note (4) to Appendix A Tables.] Instead, either 75% of the stress value in Table A-1 or two-thirds of the yield strength at temperature listed in the BPV Code, Section II, Part D, Table Y-1 should be used