ASTM A312 253MA SS Thermocouple protection tubes

With over 18 years of expertise in heat-resistant alloy pipe and tube manufacturing, GNEE supplies a full range of ASTM A312 standard 253MA thermocouple protection tubes. Our size range covers outer diameters (OD) from 6mm to 219mm, wall thicknesses from SCH5 to SCHXXS, and fixed lengths from 0.5 to 12 meters. We offer seamless cold-drawn/hot-rolled tubes, precision-cut sleeves, threaded ends, and pickled or bright annealed deep processing, all accompanied by EN 10204 3.1 Material Test Certificates (MTC).

 

Our ASTM A312 253MA (UNS S30815) heat-resistant stainless steel tubes contain 20–22% Chromium, 10–12% Nickel, 0.14–0.20% Nitrogen, and are micro-alloyed with rare earth cerium. They offer a continuous stable service temperature of up to 1100°C and can withstand short-term peak temperatures of up to 1150°C. The high-temperature creep rupture strength at 900°C is 2.5 times that of 310S stainless steel. Under thermal cycling conditions from room temperature up to 1150°C, the annual oxidation corrosion rate remains below 1.1 mm. The surface forms a dense chromium-silicon composite oxide film that resists spalling, carburization, and sulfur-bearing flue gas corrosion. Crucially, its procurement cost is approximately 30% lower than that of 310S, making it an excellent cost-effective alternative to expensive 800H and 600 nickel-based alloys.

Furthermore, ASTM A312 253MA heat-resistant tubes exhibit excellent mechanical properties, with tensile strength ≥600MPa, yield strength ≥310MPa, and elongation ≥30%, ensuring dimensional stability under long-term thermal stress. Compared to conventional 304H/316H protection sleeves, it drastically reduces thermocouple failure rates and extends service life by 1.8 to 2.2 times.

 

Alloy 253MA​ Stainless Steel Pipes Specifications

Specifications	ASTM / ASME A312 / SA312
Seamless Pipes & Tubes Sizes	1 / 2" NB - 8" NB
Welded Pipes & Tubes Sizes	6" NB - 24" NB
Outer Diameter	6.0-630mm
Schedule	SCH 10, SCH20, SCH30, SCH40, STD, SCH60, XS, SCH80, SCH120, SCH140, SCH160, XXS
Thickness	0.3mm – 50 mm
Type	Seamless / ERW / Welded/ Fabricated
Form	Round Pipes/Tubes, Square Pipes/Tubes, Rectangular Pipe/Tubes, Coiled Tubes, "U" Shape, Pan Cake Coils, Hydraulic Tubes
Length	Single Random, Double Random & Cut Length
End	Plain End, Beveled End, Treaded

 

Chemical Composition of ASTM A312 UNS S30815 Stainless Steel Pipe

Grade	–	C	Mn	Si	P	S	Cr	Ni	N	Ce
253MA / S30815	min. max.	0.05 0.10	– 0.80	1.40 2.00	– 0.040	– 0.030	20.0 22.0	10.0 12.0	0.14 0.20	0.03 0.08

 

253MA Tubes Mechanical Properties

Grade		253MA
Tensile Strength (MPa) min		600
Yield Strength 0.2% Proof (MPa) min		310
Elongation (% in 50mm) min		40
Hardness	Rockwell B (HR B) max	95
	Brinell (HB) max	217

 

ASTM A312 Stainless Steel Pipe Dimensional Tolerances

Outside diameter deviation (mm)	Outside diameter	Allowable deviation
	>10.3-48.3	+0.40/-0.80
	>48.3-114.3	+0.80/-0.08
	>114.3-219.1	+1.60/-0.80
	>219.1-457.2	+2.40-0.80
	>457.2-660.4	+3.20/-0.80
	> 660.4-864	+4.00/-0.08
	> 864-1219.2	+4.80/-0.08
Wall thickness deviation (mm)	+ Not required /-12.5%t
Bending degree (mm/m)	Reasonable straightness

 

applications of ASTM A312 253MA SS Thermocouple protection tubes

Heat treatment furnaces and muffle furnaces;
Cement and glass manufacturing kilns;
Metallurgical and petrochemical processing plants;
As well as waste incineration plants and styrene reactors.

 

253MA S30815 Stainless Steel Pipe Possible Alternative Grades

Grade	Why it might be chosen instead of 253MA
310	Carburising atmospheres require a higher nickel content
304H	Lower cost alternative, provided the operating temperature is below about 800°C
Nickel Alloys	Carburising atmospheres or temperatures above the 1100 – 1150°C maximum of 253MA.

 

Stainless Steel 253MA Pipe Price

Product Form	Size Range (OD)	Estimated Price (USD/kg)	Estimated Price (USD/Ton)
Seamless Pipe (ASTM A312)	1/2" - 8"	$5.50 – $9.20	$5,200 – $8,200
Welded Pipe (ASTM A312)	2" - 24"	$3.50 – $7.00	$3,200 – $6,000
Heat Exchanger Tube (A213)	6mm - 38mm	$6.00 – $10.50	$5,800 – $9,500

 

Quality Control

Chemical Composition Analysis: Verified using spectroscopic analysis techniques to ensure the alloy composition meets specified standards.
Mechanical Property Testing: Tensile, hardness, and impact tests are conducted to verify material performance at various temperatures.
Hydrostatic Testing: Pressure testing is performed on steel pipes to ensure leak-free performance.
Non-Destructive Testing (NDT): Includes ultrasonic, eddy current, and penetrant testing to detect any internal or surface defects.
Visual and Dimensional Inspection: Visual quality checks are performed on every steel pipe, and dimensional accuracy is verified against specifications.

Marking & Packing

SS 253MA pipes are bundled using nylon straps to prevent iron contamination and wrapped in three layers of waterproof, UV-resistant plastic film; heavy-duty PE end caps are fitted to ensure internal cleanliness. For export shipments, we use IPPC-certified fumigated plywood crates lined with high-density foam padding to ensure the pipe surfaces remain free from abrasions. Each package bears a weather-resistant label indicating the heat number, grade (UNS S30815), and size specifications.