Schedule 40 Alloy Steel Pipe

What is Schedule 40 Alloy Steel Pipe?

When searching for or learning about alloy steel pipes, you might see terms like "Schedule 40 alloy steel pipe" or "Sch alloy steel pipe." "Sch" is actually an abbreviation for "Schedule," and both have the same meaning: a parameter used to indicate the wall thickness grade and pressure resistance of steel pipes.

Schedule 40 is a key parameter identifying the wall thickness grade in piping systems, representing a standardized wall thickness specification for industrial piping. The pipe schedule number is a dimensionless value defined in ASME B36.10, which is related to the pipe's design pressure and the allowable stress of the material using a complex formula: SCH = (1,000) × (P/S), where P represents the pipe's internal working pressure (psi), and S represents the material's allowable stress (psi) at the design temperature.

In the field of alloy steel piping, Schedule 40 standards are typically used in conjunction with a variety of material specifications. Common ones include ASTM A335 (alloy steel pipe for high-temperature service), ASTM A213 (alloy steel pipe for boilers and superheater heat exchangers), and AISI 4140, 40Cr, and other chromium-molybdenum alloy steel series.

The combination of these material specifications and wall thickness standards ensures the reliable performance of piping systems under specific operating conditions.

Alloy Steel Pipe Schedule Chart

DN	NPS	OD	SCH10	SCH20	SCH30	STD	SCH40	SCH60	XS	SCH80
6	1/8	10.3	1.24	-	1.45	1.73	1.73	-	2.41	2.41
8	1/4	13.7	1.65	-	1.85	2.24	2.24	-	3.02	3.02
10	3/8	17.1	1.65	-	1.85	2.31	2.31	-	3.2	3.2
15	1/2	21.3	2.11	-	2.41	2.77	2.77	-	3.73	3.73
20	3/4	26.7	2.11	-	2.41	2.87	2.87	-	3.91	3.91
25	1	33.4	2.77	-	2.9	3.38	3.38	-	4.55	4.55
32	11/4	42.2	2.77	-	2.97	3.56	3.56	-	4.85	4.85
40	11/2	48.3	2.77	-	3.18	3.68	3.68	-	5.08	5.08
50	2	60.3	2.77	-	3.18	3.91	3.91	-	5.54	5.54
65	2/21	73	3.05	-	4.78	5.16	5.16	-	7.01	7.01
80	3	88.9	3.05	-	4.78	5.49	5.49	-	7.62	7.62
90	31/2	101.6	3.05	-	4.78	5.74	5.74	-	8.08	8.08
100	4	114.37	3.05	-	4.78	6.02	6.02	-	8.56	8.56

Alloy Steel Pipe Size & Grades

Processing Method:	Seamless and Welded
Size Range	1/8” - 48” / DN6 - 1200
Thickness Schedule	SCH 20- SCH 160, XXS
Length	6m or 12 m or Random
Standard	ASME B36.10
Surface Treatment	Blasting and Painting, Epoxy Powder FBE, 2PE, 3PE Coating
Material Grade	ASTM A335 P11 / P12 / P 5 / P9 / P91 / P92, A213 T11 / T12 / T22 / T5 / T9 / T91 / T92. 15CrMoG, 12Cr1MoVG, 12Cr5Mo, 1Cr5Mo, Cr9Mo, 10CrMo910, 12CrMo4-5

Advantages of Schedule 40 Alloy Steel

Alloy steel is a high-performance steel made by adding specific alloying elements (such as chromium, molybdenum, nickel, vanadium, etc.) to carbon steel. These alloying elements significantly improve the material's mechanical properties and weather resistance. Compared with ordinary carbon steel, Schedule 40 alloy steel pipes exhibit significant advantages in high-temperature strength, corrosion resistance, and wear resistance. For example, common chromium-molybdenum alloy steels (such as 40Cr) contain 0.8%-1.1% chromium, and this invisible chromium oxide film gives the steel resistance to high-temperature oxidation and corrosion.