Carbon and Alloy Steel Forgings for Pressure Vessels for Low Temperature Service

Steel Type	Standard	Country Code	C(%)	V(%)	Si(%)	Al(%)	Mn(%)	P(%)	N(%)
SFL1	11067	CNS	<0.3		<0.35		<1.35	<0.03
SFL1	G3205	JIS	<0.3		<0.35		<1.35	<0.03
LF1	A350	ASTM	<0.3	<0.03	0.15-0.30		0.60-1.35	<0.035
TStE 315		DIN	<0.16		<0.45	>0.02	0.7-1.5	<0.03	<0.02
SFL2	11067	CNS	<0.3		<0.35		<1.35	<0.03
SFL2	G3205	JIS	<0.3		<0.35		<1.35	<0.03
LF2	A350	ASTM	<0.3	<0.03	0.15-0.30		0.60-1.35	<0.035
SFL3	G3205	JIS	<0.2		<0.35		<0.9	<0.03
LF3	A350	ASTM	<0.2	<0.03	0.20-0.35		<0.9	<0.035
10Nil14		DIN	<0.15	<0.05	<0.35		0.3-0.8	<0.02

Carbon and alloy steel forgings are commonly used in the construction of pressure vessels for low-temperature service. These materials offer excellent mechanical properties and resistance to corrosion, making them suitable for storing and transporting substances at extreme temperatures.

Low-temperature service requires materials that can withstand the brittleness and stress that occur at low temperatures. Carbon steel forgings, such as A350 LF2 and A516 Grade 70, are commonly used for pressure vessel applications due to their low cost, high strength, and excellent impact resistance at low temperatures. They can withstand temperatures as low as -50°F (-46°C) without experiencing a significant loss of toughness.

Alloy steel forgings, on the other hand, provide enhanced resistance to corrosion and higher strength at low temperatures compared to carbon steel. Commonly used alloy steel grades for low-temperature service include A182 F11, A182 F22, and A350 LF3. These alloys contain additional elements such as chromium, molybdenum, and nickel, which improve the material's toughness, resistance to cracking, and overall performance under extreme conditions.

The selection of carbon or alloy steel forgings for pressure vessels in low-temperature service depends on various factors such as the specific application, required mechanical properties, and budgetary constraints. Engineers and designers should consider the material's ability to withstand low temperatures without becoming brittle, its resistance to corrosion, and its overall strength and toughness requirements.

It is essential to ensure that the selected carbon or alloy steel forging meets the relevant industry standards and specifications, such as ASTM A350 and ASTM A516 for carbon steel, and ASTM A182 and ASTM A350 for alloy steel. These standards specify the mechanical properties, composition, and testing requirements for materials used in pressure vessel applications.

In conclusion, carbon and alloy steel forgings are widely used in the construction of pressure vessels for low-temperature service due to their excellent mechanical properties, resistance to corrosion, and ability to withstand extreme temperatures. The selection of the material depends on the specific requirements and considerations of the application, ensuring the safe and efficient operation of the pressure vessel in low-temperature environments.