متریال LCC ( برای کار در سرویس دما پائین )

LCC : LOW CARBON CASTING

A352  :  استاندارد ساخت ( ASTM )

Standard Specification for Steel Castings, Ferritic and Martensitic, for Pressure-Containing Parts, Suitable for Low-Temperature Service

This specification covers steel castings for valves, flanges, fittings, and other pressure-containing parts intended primarily for low-temperature service.

Grade

Usual Minimum Testing

Temperatures, °F [°C]

LCA −25 [–32]

LCB −50 [–46]

LCC −50 [–46]

LC1 −75 [–59]

LC2 −100 [–73]

LC2–1 −100 [–73]

LC3 −150 [–101]

LC4 −175 [–115]

LC9 −320 [–196]

CA6NM −100 [−73]

Chemical ( TABLE 1 ) : 

LCA,LCB,LCC : C-Si-Mn  

LCA : 0.25A 0.60 0.70A  Tensile:60-85

LCB : 0.30 0.60 1.00  Tensile:65-90

LCC : 0.25A 0.60 1.20A Tensile:70-95

A For each reduction of 0.01 % below the specified maximum carbon content, an increase of 0.04 % manganese above the specified maximum will be permitted up to a maximum of 1.10 % for LCA, 1.28 % for LCB, and 1.40 % for LCC.

LC1 : C-Mo                    Tensile:65-90

LC2 : 2.5 Ni Steel       Tensile:70-95

LC2-1 : Ni-Cr-Mo   Tensile:105-130

LC3 : 3.5% Ni Steel    Tensile:70-95

LC4 : 4.5% Ni Steel    Tensile:70-95

LC9 : 9% Ni Steel        Tensile:85

CA6NM : 12.5% Cr-Ni-Mo  Tensile:110-135

Energy Value min for single specimen  : 

LCA , LCB , LC1 14J  ژول

LCC , LC2 , LC3 , LC4 16J

LC2-1 34J

LC9 , CA6NM 15J

Energy Value min Value for two specimen Or min Average of three  : 

LCA , LCB , LC1 18J  ژول

LCC , LC2 , LC3 , LC4   20J

LC2-1 41J

LC9 , CA6NM 27J

10.2 In addition to the marking required by Specification A 703/A 703M, castings that have been liquid quenched and tempered shall be marked with the letters “QT”.

Grade LC9, which shall be liquid-quenched and tempered.

-Castings shall be tempered at a minimum of 1100°F [590°C]

-Grade LC4, which shall be 1050°F [565°C],

-Grade LC9, which shall be tempered in the range of 1050 to 1175°F [565 to 635°C], followed by cooling in air or liquid.

MIN PREHEAT TEMP  ( TABLE 2 )

LCA,LCB,LCC  All thk  Min Temp : 10C

LC1 Over 15.9mm thk  Min Temp : 120C

LC1 15.9mm And Under thk Min Temp : 10C

LC2,LC2-1,LC3,LV4 All thk Min Temp : 150C

CA6NM All thk Min Temp : 10C

SUPPLEMENTARY REQUIREMENTS

S21. Heat Treatment

S21.1 Castings shall be liquid quenched and tempered.

S22. Impact Test Temperatures

S22.1 When an impact test temperature other than that listed in Table 1 is used, the lowest test temperature at which the material met the impact test requirements shall be stamped with low-stress stamps on a raised pad located immediately ahead of the material symbol; for example, 25 LCB for +25°F [–4°C] and 025 LCB for  25°F [–32°C].

S22.2 Lateral expansion of V-notch specimens shall be measured in accordance with 23.2.3.1 of Test Methods and Definitions A 370, and reported for information.

S23. Carbon Equivalent

S23.1 When specified on the order the maximum carbon equivalent shall be:

Grade Carbon Equivalent, max

LCA Max 0.50

LCB Max 0.50

LCC Max 0.55

S23.2 Determine carbon equivalent, CE, as follows:

CE = C + Mn/6 + ( Cr + Mo + V ) / 5 + ( Ni + Cu ) / 15