INSTALLATION

METAL TO METAL SEATED VALVES

 Installation welding should be done in accordance with ASME Boiler and Pressure Vessel Code, Section I, Part PW, or ANSI B31.1 PARA 127.

  1. Close valve tightly before welding to protect seat from heat distortion and weld splatter.
  2. Allow 1/16" gap between bottom of socket, or butt weld end, and end of pipe (PW 41.5.7, or ANSI B31.1 PARA 127.3.3).
  3. Preheat and postweld heat treat as required. (See Table 1).

TABLE 1
PREHEAT AND POSTWELD HEAT TREAT REQUIREMENTS

P-1
SA-105		 P-5
SA-182 GR. F22		 P-8
SA-182 GR. F316
PREHEAT
50° F
(A100.4.1)*		 PREHEAT
400° F
(A100.4.4)*		 PREHEAT
NONE REQUIRED
(A100.4.7)*
POST WELD HEAT TREAT
NONE REQUIRED
(PW-39)		 POST WELD HEAT TREAT
REQUIRED WHEN NOMINAL
WALL THICKNESS EXCEEDS 5/8":
1250° F 1 1/4 HR Min. (PW-39)		 POST WELD HEAT TREAT
NONE REQUIRED
(PW-39)
* ASME BOILER AND PRESSURE VESSEL CODE, SECTION I, PART PW-38

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