ASTM A105 Forged Tube Sheet
ASTM A105/ A105M, identical with ASME SA-105/ SA-105M, is the standard specification for carbon steel forgings for piping applications. The application of ASME SA-105 forgings is endorsed by a series of ASME Boiler and Pressure Vessel Codes and ASME B31 Codes. However, the misuse of this material is commonly seen in some engineering practices. A typical misuse is that some fabricators may manufacture tubesheets from ASTM A105/ ASME SA-105
1. ASTM A105 Scope
1.1 This specification covers forged carbon steel piping components for ambient- and higher-temperature service in pressure systems. Included are flanges, fittings, Valves, and similar parts ordered either to dimensions specified by the purchaser or to dimensional standards such as the MSS, ASME, and API specifications referenced in Section. Forgings made to this specification are limited to a maximum weight of 10000 lb [4540 kg]. Larger forgings may be ordered to Specification A 266/A 266M. Tubesheets and hollow cylindrical forgings for pressure vessel shells are not included within the scope of this specification. Although this specification covers some piping components machined from rolled bar and seamless tubular products (see), it does not cover raw material produced in these product forms.
1.2 Supplementary requirements are provided for use when additional testing or inspection is desired. These shall apply only when specified individually by the purchaser in the order.
1.3 Specification A 266/A 266M covers other steel forgings and Specifications A 675/A 675M and A 696 cover other steel bars.
1.4 This specification is expressed in both inch-pound units and SI units. However, unless the order specifies the applicable "M" specification designation (SI units), the material shall be furnished to inch-pound units.
1.5 The values stated in either inch-pound units or SI are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.
Note 1.. The dimensionless designator NPS (nominal pipe size) has been substituted in this standard for such traditional terms as "nominal diameter", "size", "and nominal size".
2. ASTM A105 Referenced Documents
A266/A266M Specification for Carbon Steel Forgings for Pressure Vessel Components
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A675/A675M Specification for Steel Bars, Carbon, Hot-Wrought, Special Quality, Mechanical Properties
A696 Specification for Steel Bars, Carbon, Hot-Wrought or Cold-Finished, Special Quality, for Pressure Piping Components
A788 Specification for Steel Forgings, General Requirements
A961 Specification for Common Requirements for Steel Flanges, Forged Fittings, Valves, and Parts for Piping Applications
API-600 Flanged and Butt-Welding-End Steel Gate Valves
API-602 Compact Design Carbon Steel Gate Valves for Refinery Use
B16.10 Face-to-Face and End-to-End Dimensions of Ferrous Valves
B16.11 Forged Steel Fittings, Socket Weld, and Threaded
B16.34 Valves-Flanged, Threaded and Welding End
B16.47 Large Diameter Steel Flanges
B16.5 Dimensional Standards for Steel Pipe Flanges and Flanged Fittings
B16.9 Wrought Steel Buttwelding Fittings
Section IX Welding Qualifications
SP44 Standard for Steel Pipe Line Flanges
CHEMICAL REQUIREMENTS ASTM A105
Element Composition, %
Carbon 0.35 max
Phosphorus 0.035 max
Sulfur 0.040 max
Copper 0.40 max (1)
Nickel 0.40 max (1)
Chromium 0.30 max (1-2)
Molybdenum 0.12 max (1-2)
Vanadium 0.08 max
(1) The sum of copper, nickel, chromium, molybdenum and vanadium shall not exceed 1.00%.
(2) The sum of chromium and molybdenum shall not exceed 0.32%.
For each reduction of 0.01% below the specified carbon maximum (0.35%), an increase of 0.06% manganese above the specified maximum (1.05%) will be permitted up to a maximum of 1.35%.
In the standard specification, it states clearly in para 1.1 that “tubesheets and hollow cylindrical forgings for pressure vessel shells are not included within the scope of this specification”. Hence ASTM A105/ ASME SA-105 forgings cant be used for the manufacture of tubesheets. The tubesheet is an important pressure vessel component for heat exchangers, heaters, superheaters and evaporators, etc. For a carbon steel tubesheet, if it is not allowed to be made from A105, what material should it be made from? The answer is ASTM A266 or ASME SA-266 forging as stated in para. 1.3.