STKM11A ERW Carbon Steel Welded Pipe Precision Automotive Steel Tube

Material 

Electric-Resistance Welded (ERW) low-carbon steel tubing manufactured to JIS G3445 STKM11A and supplied as precision, cold-sized round tubes for automotive and machinery applications. Typical forming includes bending, flaring, flanging and flattening with consistent surface and weld integrity per precision-tube standards.

Specifications

• Process: ERW (high-frequency), cold sizing; optional annealed (+A) or normalized (+N) after sizing.

• Supply conditions: +CR1 / +CR2 (as-welded & cold-sized), +A (soft annealed), +N (normalized) to match downstream forming needs.

• Standards typically matched: JIS G3445 (STKM series), EN 10305-3 (E-grades), ASTM A513 (Types 1/2 mechanical tubing), GB/T 13793 (ERW steel pipe).

Key Features

• Automotive-grade precision: Tight OD/WT tolerances and specified maximum surface roughness per EN 10305-3 for precision tubes.

• Formability & weldability: Low carbon (C ≤0.12%) and Mn ≤0.60% promote easy bending and flaring with stable weldability.

• Consistent weld seam quality: Flash-in/flash-out control available; internal flash controlled to ≤0.005 in (≈0.13 mm) when specified.

• Verified straightness: Meets typical ASTM A513 straightness criteria 1/32 in per 3 ft (~0.8 mm/m); tighter options available by agreement.

• Optional heat treatment windows: +A for maximum ductility; +N for balanced strength/ductility; +CR1/+CR2 when higher as-welded strength is desired.

Chemical Composition 

Mechanical Properties

Governing Standards

• JIS: JIS G3445 (STKM11A/12A/12C) carbon steel tubes for machine structure.

• EN: EN 10305-3 (E155/E190/E195) welded, cold-sized precision tubes; precision tolerances and surface roughness defined; typical field—automotive.

• ASTM/ASME: ASTM/ASME A513 (Types 1 & 2) ERW carbon steel mechanical tubing with specific OD/WT/straightness tolerances; flash control options.

• GB (China): GB/T 13793 ERW steel pipe (general); precision applications often align with EN 10305-3 requirements on request.

• GOST (Russia): GOST 10705/10704 welded steel pipes (general-purpose baselines) used for referencing dimensional tolerances in CIS markets.

Application Fields

General: Automotive, machinery, furniture, appliances, bicycles, and general engineering precision tubing.

Automotive examples (where it is used within the system):

• Chassis & body: seat structures, cross-members, crash-bracing.

• Steering & suspension: steering columns/shafts, shock absorber shells, stabilizer bar sleeves.

• Powertrain & fuel: fuel rails, EV battery pack frames, coolant lines (with post-coating).

• Interior mechanisms: slider rails, hinge arms.

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.