China GB/T 18248-2021 Manufacturer and Supplier

GB/T 18248-2021

Short Description:

GB/T 18248-2021 standard

Seamless steel tubes for gas cylinder

Payment: 30% deposit, 70% L/C or B/L copy or 100% L/C at sight

Min.Order Quantity: 1 PC

Supply Ability: Annual 20000 Tons Inventory of Steel Pipe

Lead Time: 7-14 days if in stock, 30-45 days to produce

Packing: Black Vanishing, bevel and cap for every single pipe; OD below 219mm need to pack in bundle, and each bundle no exceed 2 tons.

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Product Detail

Product Tags

Overview

Standard: GB/T 18248-2021

Grade Group: 37Mn，30CrMo，35CrMo，42CrMo，30CrMnSiA，34CrMo4, etc

Thickness: 1 - 100 mm

Outer Diameter(Round): 10 - 1000 mm

Length: Fixed length or random length

Section Shape: Round

Place of Origin: China

Certification: ISO9001:2008

Alloy Or Not: Alloy

Application: Gas cylinder tube

Surface Treatment: As customer's requirement

Technique: Hot Rolled/Cold Drawn

Heat treatment: Annealing/normalizing

Special Pipe: Thick Wall Pipe

Usage: Gas cylinder tube

Test: ET/UT

Application

Seamless steel pipes used for manufacturing the shells of gas cylinders and accumulators

Main Grade

Grade Of Alloy Structural Steel: 37Mn，30CrMo，35CrMo，42CrMo，30CrMnSiA，34CrMo4

Chemical Component

Steel Grade	Chemical composition
Steel Grade	C	Si	Mn	P	S	P+S	Cr	Mo	Ni	Cu
37Mn^a	0.34～0.38	0.10～0.35	1.35～1.75	≤0.020	≤0.010	≤0.025	≤0.30	-	≤0.30	≤0.20
30CrMo^a,c	0.26～0.33	0.17～0.37	0.40～0.70	≤0.020	≤0.010	≤0.025	0.80～1.10	0.15～0.25	≤0.30	≤0.20
35CrMo^a	0.32～0.40	0.17～0.37	0.40～0.70	≤0.020	≤0.010	≤0.025	0.80～1.10	0.15～0.25	≤0.30	≤0.20
42CrMo^a,d	0.38～0.45	0.17～0.37	0.50～0.80	≤0.020	≤0.010	≤0.025	0.90～1.20	0.15～0.25	≤0.30	≤0.20
30CrMnSiA	0.28～0.34	0.90～1.20	0.80～1.10	≤0.020	≤0.020	≤0.030	0.80～1.10	≤0.10	≤0.30	≤0.20
34CrMo4	0.30～0.37	0.15～0.35	0.60～0.90	≤0.020	≤0.010	≤0.025	0.90～1.20	0.15～0.30	≤0.30	≤0.20
a. It should satisfy V + Nb + Ti + B + Zr ≤ 0.15%. b. According to the requirements of the buyer, after negotiation between the supplier and the buyer, and with the stipulation noted in the contract, it can be specified that Al should be greater than or equal to 0.020%. c. Orders can be placed for 30CrMoE, whose chemical composition is the same as that of 30CrMo. d. Orders can be placed for 42CrMoE, whose chemical composition is the same as that of 42CrMo.

Mechanical Property

Grade	Recommended heat treatment regime				Longitudinal mechanical properties
	Quenching (Normalizing)		Tempering		tensile strength R_mPa	Lower yield strength R_eL^BMPa	Elongation after fractureA%	Impact energy absorption
	temperature℃	Coolant	temperature℃	Coolant	Not less than			Test temperature℃	KV₂J Not less than
37Mn	820-860	water	550-650	Air	750	630	16	-50	27
37Mn	830-870	Air	-	-	700	520	16	-20	27
30CrMo	860-900	water、Oil	490-590	water、Oil	930	785	12	-50	27
35CrMo	830-870	water、Oil	500-600	water、Oil	980	835	12	-50	27
42CrMo	830-870	Oil	510-610	water、Oil	1080	930	12	-50	27
30CrMnSiA	860-900	Oil	470-570	water、Oil	1080	885	10	Room temperature	27
a.The tensile test temperature was room temperature.b.If R_eL cannot be measured,R_p0.2can be me measured instead of R_eLc.When the purchaser specifies 4130X or 30CrMoE as the grade for delivery, the reference value of mechanical properties can be based on 30CrMo.d.When the purchaser specifies 34CrMo4 grade for delivery, the mechanical properties can refer to 35CrMo.e.When the purchaser specifies 4142 or 42CrMoE grades for delivery, the reference value of mechanical properties can be based on 42CrMo.

Tolerance

Steel pipe manufacturing methods	range of sizes	Permissible Variations in Outside Diameter	Permissible deviation of wall thickness
			Basic level PA	advanced level PC
Hot Rolled	D＜339.7	±1%D	+25%Smin 0	+25%Smin 0
	D≥339.7		+30%Smin 0	+25%Smin 0
Cold drawn(rolled) Ppipe	all	±0.75%D	+22.5%Smin 0	+15%Smin 0

Test Requirement

In addition to ensuring the chemical composition and mechanical properties, hydraulic tests, electromagnetic inspections, non-metallic inclusions tests, and non-destructive tests (ultrasonic testing and magnetic particle testing) will also be conducted.