42CrMo Precision Seamless Steel Pipe (High-Strength Low-Alloy Mechanical Tubing)

Material

42CrMo is a Cr-Mo alloy steel per GB/T 3077, commonly quenched and tempered for high strength, toughness, and fatigue resistance. Used as precision seamless tubing, it offers tight dimensional control and clean internal surfaces suitable for machining, honing, and high-load mechanical service. 

Specifications

• Standards for precision/mechanical tube:
  GB/T 3639 (seamless cold-drawn/rolled precision tubes), EN 10305-1 (seamless cold-drawn precision tubes), EN 10297-1 (seamless tubes for mechanical and general engineering), ASTM A519 (seamless carbon and alloy mechanical tubing). 

• Typical size envelope:
  OD up to 323.8 mm under ASTM A519; EN 10305-1 allows OD ≤ 380 mm. Lengths per order. 

• Delivery conditions: +A (annealed), +SR (stress relieved), +QT (quenched & tempered), +N (normalized), as specified. 

• Precision attributes: EN 10305-1 defines tight OD/WT tolerances and maximum surface roughness requirements for precision applications. ASTM A519 provides detailed OD tolerances; hot-finished tolerance examples include ±0.020″ up to 3″ OD, scaling with size. 

Key Features

• High tensile and yield strength with good impact toughness after Q&T. 

• Good hardenability and stability across section sizes (42CrMo family).

• Manufactured to precision tubing standards for concentricity, straightness, and controlled roughness. 

Our Advantages

1. Tight tolerances & finish for ready-to-machine parts
   We supply per EN 10305-1 precision limits (tight OD/WT tolerances and specified Ra caps) and ASTM A519 tolerance classes, reducing pre-machining allowance and scrap. 

2. Verified mechanical properties in the delivered condition
   When ordered +QT, we target the 42CrMo/42CrMo4 property window (e.g., ≥930 MPa YS, ≥1080 MPa UTS at reference size; EN 42CrMo4 +QT ranges by diameter). Each lot ships with EN 10204 3.1 MTRs. 

3. Broad standards coverage and cross-grade expertise
   We can certify to GB/T 3639, EN 10305-1, EN 10297-1, and ASTM A519, and we help select equivalents such as 42CrMo4 (EN 1.7225), AISI/SAE 4140, or JIS SCM440 to meet your print.

4. Size range that fits real projects
   We cover mechanical tube sizes up to 12 ¾″ (323.8 mm) under ASTM A519 and up to 380 mm OD under EN 10305-1, with custom lengths and heat treatments. 

5. NDT & quality controls for reliability
   Precision tube standards call out leak-tightness verification/EM testing and mechanical tests (tension, hardness, flaring) as applicable; we align our QA plan accordingly. 

Chemical Composition

Mechanical Properties 

Governing Standards

• GB (China): GB/T 3077 (42CrMo steel); GB/T 3639 for precision cold-drawn/cold-rolled seamless tubes. 

• EN (Europe): EN 10305-1 (precision seamless cold-drawn tubes); EN 10297-1 (seamless tubes for mech/general engineering); EN 10083-3 (42CrMo4 steel for Q&T).

• ASTM/ASME (US): ASTM A519 / ASME SA519 (seamless carbon/alloy mechanical tubing). 

• JIS (Japan): JIS G4053 (SCM440, low-alloy steels for machine structural use). 

• GOST (Russia): GOST 8734-75 (cold-formed/precision seamless tubes, dimensions & tolerances) and GOST 4543 (structural alloy steels, incl. 40X family). 

Application Fields

• General scope: automotive, powertrain, heavy machinery, mining, hydraulic systems, oilfield tools, gear/shaft components. 

• Typical uses in each field:
  Automotive & off-highway: drive/axle shafts, steering knuckles, cylinder tubes (EN 10305-1 precision). Industrial hydraulics: honed cylinder barrels, piston rods (precision ID/OD). Energy & oilfield: drill-pipe tool joints, couplings. Gear trains: large gears, pinions, crankshafts requiring Q&T strength. 

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,

it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.