Low and Intermediate Alloy Steel Gate Valves – Materials and Services

1. SCOPE

…………………………………………………

1. REFERENCES
2. GENERAL
3. ADDITIONAL MATERIAL REQUIREMENTS

1. Scope

1.1 This specification is to assist the user in the application and adaption of the gate valves described in

PIP PNSMV013. The valves are of low and intermediate alloy steel, with bolted, welded or pressure-seal

bonnet, flanged (raised faced) or welding ended (butt or socket), and are of outside screw and yoke

(OS&Y) construction. Nominal pipe sizes NPS 1

/2 to 24 for Classes 150 to 1500 are covered.

1.2 This specification shall be used in conjunction with SES P18-G01.

1.3 This specification is one of a four part series for gate valves, each of which represents a group of like

materials, see 3.2.

1. References

Reference is made in this specification to the following documents. The latest issues, amendments, and

supplements to these documents shall apply unless otherwise indicated.

SABIC Engineering Standards (SES)

P18-G01 Design Limitations and Applications of Valves

P18-S01 Carbon Steel Gate Valves – Materials and Services

P18-S03 Stainless Steel Gate Valves – Materials and Services

P18-X01 Gate Valve Data Sheet

American Society for Testing and Materials (ASTM)

A 193 Alloy-Steel and Stainless Steel Bolting Materials for High Temperature Service

American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel Code – Section I

National Association of Corrosion Engineers (NACE)

MR0175 Standard Material Requirements – Sulfide Stress Cracking

Process Industry Practices (PIP)

PNSMV003 Carbon Steel – Gate Valve Descriptions

PNSMV013 Low and Intermediate Alloy Steel – Gate Valve Descriptions

PNSMV023 Stainless Steel – Gate Valve Descriptions

PNSMV033 Bronze and Iron – Gate Valve Descriptions

1. General

3.1 The low and intermediate alloy steel gate valves described in PIP PNSMV013 and this specification

shall be used in general process services, which shall include but not be limited to general hydrocarbons,

super heated steam (ASME Section I), high pressure condensate, boiler feed water, reformed gas,

process gas, natural gas, synthesis gas, hydrogen rich hydrocarbons, hydrogen, ammonia, and caustic

wash. These low and intermediate alloy steel gate valves contain 1 to 9 chromium plus various amounts of

molybdenum.

3.2 The other specifications in this series are

a. SES P18-S01, which covers carbon steel gate valves described in PIP PNSMV003, and used in

general process services

b. SES P18-S03, which covers stainless steel gate valves described in PIP PNSMV023, and used

in corrosive services

c. Gate valves described in PIP PNSMV033, and used in utility services

3.3 Valves in new piping systems shall conform to PIP PNSMV013 and this specification. Valves for

maintaining or tie-in to existing systems may be in accordance with original specifications.

3.4 PIP PNSMV013 describes the valves, their components, and their materials of construction. The trim
for gate valves comprises the stem, body and gate seating surfaces, bushing and small internal parts that
contact the service fluid.
3.5 The valves have unique valve number designations, for example GA-140, by which they are referred to
in the PIP line classes. See PIP PNSMV013 Section 6 for applicable line classes.
3.6 All design, material, service, inspection, marking, documentation, shipping and other requirements
shall be specified on the data sheet SES P18-X01. This shall be attached to the requisition/purchase order.
4. Additional Material Requirements
For services where the materials specified in PIP PNSMV013 are inadequate, the following requirements
shall be met:
4.1 Materials shall be suitable for continuous exposure at the service conditions and ratings specified.
4.2 Valve components in rubbing or sliding contact shall not gall.
4.3 The corrosion resistance of body-bonnet and packing gland bolting, and ring joint gasket material shall
be at least equal to the material of the body, bonnet and yoke. However, the bolting material is not required
to be more corrosion resistant than austenitic stainless AISI type 304 (in accordance with ASTM A 193)
unless otherwise specified in the purchase order.
4.4 Steam service can be abrasive, when condensate is entrained. The valve trim seats shall be integral or
welded, with the backseating surface hardfaced.
4.5 Chrome molybdenum materials, 2
/4 Cr-1Mo in particular, tend to degrade when subjected to repeated
weldings and subsequent stress reliefs. This shall be mitigated either by metallurgical control or by step
cooling. A third alternative shall be to limit the number of heat treatments, to limit the total tempering.
1
4.6 Cyanides, acids, acid salts and wet H2S, or sour service promote sulfide (stress corrosion) cracking.
This situation shall be mitigated by maintaining maximum ductility in the valve parts. Maximum hardness
limits shall be as specified in NACE MR0175. Body-to-bonnet bolting shall be in accordance with
NACE MR0175 Class III. However, when the valve is to be insulated, or buried, it shall be in accordance
with NACE MR0175 Class I or II. Weldments shall be stress relieved in accordance with NACE sections 3
and 4.
4.7 The packing material shall be chemically compatible with the fluid, and have sufficient sealing
properties at the temperature of operation. Packing shall be asbestos-free, and corrosion inhibited, to avoid
stem pitting. In hydrocarbon services, packing and stem seals shall not be pure polymer/elastomer unless
the valves have been qualified as fire safe.
4.8 The identification plate material shall be austenitic stainless steel or nickel alloy.