低合金鋼及碳鋼低溫作業/ 判定 MDMT

1. Tabular values for this figure are provided in Table UCS-66.
   
2. See UCS-66(a).
   

3. For bolting and nuts, the following impact test exemption temperatures shall apply:
   

   
   

4. When no class or grade is shown, all classes or grades are included.
   
5. The following shall apply to all material assignment notes:
   
   1. Cooling rates faster than those obtained by cooling in air, followed by tempering, as permitted by the material specification, are considered to be equivalent to normalizing or normalizing and tempering heat treatments.
      
   2. Fine grain practice is defined as the procedure necessary to obtain a fine austenitic grain size as described in SA-20.
      
   3. Normalized rolling condition is not considered as being equivalent to normalizing.
      
6. Castings not listed in Notes (1) and (2) below shall be impact tested. </li>
   

1. Curve A applies to the following:
   
   1. all carbon and all low alloy steel plates, structural shapes, and bars not listed in Curves B, C, and D below
      
   2. SA-216 Grades WCB and WCC if normalized and tempered or water-quenched and tempered; SA-217 Grade WC6 if normalized and tempered or water-quenched and tempered
      
   3. A/SA-105 forged flanges supplied in the as-forged condition
      
2. Curve B applies to the following:
   
   1. see below:
      A/SA-105 forged flanges produced to fine grain practice and normalized, normalized and tempered, or quenched and tempered after forging
      SA-216 Grade WCA if normalized and tempered or water-quenched and tempered
      SA-216 Grades WCB and WCC for thicknesses not exceeding 2 in. (50 mm) , if produced to fine grain practice and water-quenched and tempered
      SA-217 Grade WC9 if normalized and tempered
      SA-299
      SA-414 Grade A
      SA-515 Grade 60
      SA-516 Grades 65 and 70 if not normalized
      SA-612 if not normalized
      SA-662 Grade B if not normalized
      SA/EN 10028-2 Grades P235GH, P265GH, P295GH, and P355GH as rolled
      SA/AS 1548 Grades PT430NR and PT460NR
      SA/GB 713 Grade Q345R if not normalized
      
   2. except for cast steels, all materials of Curve A, if produced to fine grain practice and normalized, that are not listed in Curves C and D below
      
   3. all pipe, fittings, forgings and tubing not listed for Curves C and D below
      
   4. parts permitted under UG-11 even when fabricated from plate that otherwise would be assigned to a different curve
      
3. Curve C applies to the following:
   
   1. see below:
      SA-182 Grades F21 and F22 if normalized and tempered
      SA-302 Grades C and D
      SA-336 F21 and F22 if normalized and tempered, or liquid quenched and tempered
      SA-387 Grades 21 and 22 if normalized and tempered, or liquid quenched and tempered
      SA-516 Grades 55 and 60 if not normalized
      SA-533 Types B and C Class 1
      SA-662 Grade A
      SA/EN 10028-2 Grade 10CrMo9–10 if normalized and tempered
      
   2. all materials listed in 2(a) and 2(c) for Curve B if produced to fine grain practice and normalized, normalized and tempered, or liquid quenched and tempered as permitted in the material specification, and not listed for Curve D below
      
4. Curve D applies to the following:
   SA-203
   SA-299 if normalized
   SA-508 Grade 1
   SA-516 if normalized or quenched and tempered
   SA-524 Classes 1 and 2
   SA-537 Classes 1, 2, and 3
   SA-612 if normalized
   SA-662 if normalized
   SA-738 Grade A
   SA-738 Grade A with Cb and V deliberately added in accordance with the provisions of the material specification, not colder than −20°F (−29°C)
   SA-738 Grade B not colder than −20°F (−29°C)
   SA/AS 1548 Grades PT430N and PT460N
   SA/EN 10028-2 Grades P235GH, P265GH, P295GH, and P355GH if normalized
   SA/EN 10028-3 Grade P275NH
   SA/GB 713 Grade Q345R if normalized
   

NOTES:

1. Alternative Ratio = S* E* divided by the product of the maximum allowable stress value from Table UCS-23 times E , where S* is the applied general primary membrane tensile stress and E and E * are as defined in Figure UCS-66.2, Note (3)
   
2. See UCS-66(b).
   

NOTES:

1. Alternative Ratio = S* E* divided by the product of the maximum allowable stress value from Table UCS-23 times E , where S* is the applied general primary membrane tensile stress and E and E * are as defined in Figure UCS-66.2, Note (3)
   
2. See UCS-66(b).