ASTM A192 Seamless Steel Pipe

ASTM A192 - Standard specification for seamless carbon steel boiler tubes for high-pressure service.

This guide covers standard specifications for minimum-wall-thickness, seamless carbon steel boiler and superheater tubes for high-pressure service. The steel shall conform to the required chemical composition for carbon, manganese, phosphorus, sulfur, and silicon. The tubes shall have a hardness number not exceeding a specific value. The following mechanical tests shall be conducted, namely: flattening test; flaring test; hardness test; and hydrostatic test.

Specifications:
Outer diameter: 12.7mm to 177.8mm [1/2 to 7 inches.]
Wall thickness: 2.2mm to 25.4mm [0.085 to 1.000 inches.]

Other sizes of steel pipes are also available, but they must meet all other requirements of the standard. However, the mechanical property requirements do not apply to pipes with an inner diameter less than 1/8 inch (3.2 mm) or a thickness less than 0.015 inches (0.4 mm).

Applications:

ASTM A192 steel pipes are mainly used for:
Heating surface pipes, superheaters, reheaters, etc. of high-pressure boilers (working pressure is generally ≤9.8MPa, temperature 450℃~650℃).
Heat exchangers (such as evaporator tubes of waste heat boilers in petrochemical plants).
High temperature and high pressure equipment in the power, chemical, petroleum, shipbuilding and other industries.

Features:
1. High pressure resistance: high minimum burst pressure, suitable for high pressure environments.
2. High temperature resistance: can operate stably at 450℃~650℃.
3. Hardness requirement: ≤137HB when wall thickness ≥5.1mm, ≤77HRB when wall thickness <5.1mm

Chemistry composition

C, %	Mn, %	Si, %	P, %	S, %
0.06-0.18	0.27-0.63	0.25 max	0.035 max	0.035 max

Mechanical properties

Tensile Strength , MPa	Yield Strength , MPa	Elongation, %	Hardness, HB, WT≥5.1mm	Hardness, HRB, WT＜5.1mm
325 min	180 min	35 min	137 max	77 max

Outside diameter & tolerance

Hot rolled	Outside Diameter, mm	Tolerance, mm
	OD≤101.6	+0.4/-0.8
	101.6＜OD≤177.8	+0.4/-1.2
Cold Drawn	Outside Diameter, mm	Tolerance, mm
	OD＜25.4	±0.10
	25.4≤OD≤38.1	±0.15
	38.1＜OD＜50.8	±0.20
	50.8≤OD＜63.5	±0.25
	63.5≤OD＜76.2	±0.30
	76.2≤OD≤101.6	±0.38
	101.6＜OD≤177.8	+0.38/-0.64

Wall thickness & tolerance

Hot rolled	Outside Diameter, mm	Tolerance, %
	OD≤101.6, WT≤2.4	+40/-0
	OD≤101.6, 2.4＜WT≤3.8	+35/-0
	OD≤101.6, 3.8＜WT≤4.6	+33/-0
	OD≤101.6, WT>4.6	+28/-0
	OD>101.6, 2.4＜WT≤3.8	+35/-0
	OD>101.6, 3.8＜WT≤4.6	+33/-0
	OD>101.6, WT>4.6	+28/-0
Cold Drawn	Outside Diameter, mm	Tolerance, %
	OD≤38.1	+20/-0
	OD>38.1	+22/-0

Production process:
Manufacturing method: Made by seamless process (hot rolling or cold drawing), and undergo appropriate heat treatment to ensure that its performance meets the standard requirements.

Heat treatment:
Hot-rolled tubes usually do not require heat treatment.
Cold-drawn tubes need to be annealed at ≥650℃ to eliminate work hardening.

Surface treatment and protection:
According to different needs, steel pipes can be surface treated by painting, oiling, hot-dip galvanizing, etc. to improve their corrosion resistance and service life.

Testing requirements:
Hydrostatic test or non-destructive testing (such as ultrasonic testing) for each pipe.
Flattening test, expansion test, hardness test (sampling for each batch)

Flattening test: 2 steel pipes are taken from each batch, and 1 sample is taken from each end of each steel pipe for flattening test to test the deformation and anti-destruction ability of the steel pipe when subjected to axial pressure, to ensure that the steel pipe can withstand the possible external pressure in actual use.

Expansion test: 2 steel pipes are also taken from each batch, and 1 sample is taken from each end of each steel pipe for expansion test to evaluate the performance of the steel pipe during radial expansion, to prevent cracks or ruptures of the steel pipe during installation or use due to expansion operation.

Hydrostatic test: Each steel pipe should be subjected to hydrostatic test to test the sealing and pressure resistance of the steel pipe, to ensure that the steel pipe will not leak when subjected to internal fluid pressure, to ensure the normal operation of high-pressure equipment. Or according to the requirements of the purchaser, non-destructive testing can also be used instead of hydrostatic test.

Product identification and quality control:
The relevant standard number, steel grade, size, production and other information should be marked on the steel pipe for traceability and quality control. Strict quality inspections are required during the production process, including raw material inspection, intermediate inspection during the production process, and finished product inspection to ensure that the quality of the steel pipe meets the requirements of the ASTM A192 standard.

Related standards:
ASME SA192: Equivalent standard adopted by the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code.
Similar grades in China: Equivalent to domestic 10# steel boiler tubes.

Market application:
With the growing demand for high-temperature and high-pressure equipment in the power and chemical industries, ASTM A192 steel pipes have broad prospects in power plant boilers, petrochemical plants, ship power systems and other fields.

Read more: What are seamless boiler tubes and how are they made? or ASME SA179 Boiler tubes