Normalized Steel Pipes (NBK/+N Condition) represent a standardized delivery state where steel tubes undergo normalizing heat treatment after cold forming processes. These normalized seamless tubes are heated to 30-50°C above Ac3 (for hypoeutectoid steel) or Accm (for hypereutectoid steel) temperatures, maintained at this level, then cooled in air to achieve
The manufacturing process involves cold drawing or cold rolling followed by precisely controlled heating and natural air cooling. This simplified heat treatment methodology requires no specialized rapid cooling equipment, making it both efficient and cost-effective while delivering consistent material properties. The resulting normalized condition provides optimal balance between strength and processability for general engineering applications.
These NBK condition pipes develop fine-grained pearlitic (or pearlitic-ferritic) microstructure through the normalizing process, completely free from martensitic brittle phases that occur after quenching. The homogeneous material structure exhibits significantly reduced internal stresses compared to non-heat-treated tubes, ensuring enhanced dimensional stability and reliable performance in various operating conditions.
The balanced mechanical properties of Normalized Steel Pipes demonstrate higher strength and hardness than annealed tubes (GBK condition) while maintaining better plasticity and toughness than non-heat-treated hard condition tubes (BK). Typical Q235 material normalized pipes achieve tensile strength of 400-550MPa with elongation ≥21%, providing excellent all-around performance for general mechanical applications.
These normalized steel tubes offer good processability for immediate machining, welding, and bending operations without requiring additional stress relief annealing. The simplified manufacturing process reduces production cycles and costs while maintaining straightness and roundness accuracy suitable for conventional mechanical assembly requirements.
Technical Advantages:
• Refined grain structure through normalized heat treatment
• Balanced mechanical properties between strength and toughness
• Reduced internal stresses for improved dimensional stability
• Immediate processability without additional heat treatment
• Cost-effective manufacturing with simplified processing
• Consistent performance for general engineering applications
Normalized Steel Pipes serve effectively in mechanical manufacturing for gear blanks, shaft sleeves, and support brackets where balanced performance and machining efficiency are prioritized. These normalized condition tubes are widely used in medium-low pressure fluid transportation systems including water supply, drainage, and compressed air pipelines, as well as general service piping in chemical and power industries.
The automotive and agricultural machinery sectors utilize these pipes for chassis supports and transmission shafts where standardized processing requirements dominate. General mechanical applications include pump housings, fan casings, and impeller components that benefit from the consistent mechanical properties and reliable processability of normalized tubes.
Supported by Tenjan’s 21 years of seamless tube specialization and 30 years of technical expertise in our R&D team, we provide customized normalized solutions tailored to your specific application requirements. Our advanced manufacturing capabilities ensure each Normalized Steel Pipe (NBK/+N Condition) meets exact specifications for materials, dimensions, surface quality, and mechanical properties, delivering reliable performance for your engineering applications.
Custom Sizes OD10-108mm-ASTM/EN/DIN/JIS/GOST Certified -Small-Batch Friendly
| Parameter | Key Features |
| Outer Diameter | 10-108mm (0.39″-4.25″) • Fully customizable |
| Wall Thickness | 1-20mm (0.039″-0.79″) • ±0.1mm precision tolerance |
| Material | Carbon Steel • Alloy Steel • Special grades available |
| Process | Cold Drawn Cold Rolled for superior finish |
| Standard | Typical Grades We Supply |
|
GB |
DT4,Y15,10#,20#,20G,Q235,25Mn,35#,45#,55# 16Mn,Q345B(Q355B),Q345C(Q355C),Q345D(Q355D),Q345E(Q355E),Q420,Q460,20Cr,40Cr, 15CrMo,20CrMo,30CrMo,35CrMo,42CrMo,20CrNiMo,40CrNiMo,20CrMnTi,20Mn2,40Mn2,40MnB,35MnB, 35Mn15CrMn,20CrMn,20CrMnMo,38CrMoAL,36Mn2V,38Mn2V,40MnMoV,15Mo3,16Mo3,31CrMoV9 |
|
ASTM |
1215,1008,1010,1020,A105,A106 Gr.B,A36,1026,1035,1045,1055,SA179,SA192 Gr·50,Gr·55,Gr·65,5120,5140,4130,4135,4140,8620,4340,SAE 5120,1524,1340,15B41,SAE5115,SAE 5120,SCM23 |
| EN | DC01,11SMn30,P235TR1,P195GH,P265TR2,E235 E355,ST52,S355JR,S355JO,S355J2,S355NL,S420N,S420NL,S460NL,20Cr4, 41Cr4,13CrMo4-5,20CrMo4,25CrMo4,34CrMo4,42CrMo4,20NiCrMo2,34CrNiMo6,20MnCr5, 22Mn6,42Mn6,42MnB4,34MnB5,37Mn5,16MnCr5,20CrMo5. |
| JIS | SUM22,S10C,STKM11A,STPT370,STB35,S20C,STKM12,STKM13,STPT410,STB42,SS400,S35C,S45C,S55C SCr22,SCr440,SCM415,SCM420,SCM430,SCM435,SCM440, SNCM220,SNCM439,SMnC420H,SMn420,SMn438, SMnC420H |
| DIN | DC01,11SMn30,CK10,C10,ST35.8,C20,CK20,ST45.8,St37,S235JR,C26D,CK35,CK45,CK55 |
| GOST |
08КП,10,20,Ст3сп,25,35,45,5515Г2, 09Г2C/10Г2C1,15Г2,14Г2С,C355,20Х,40X,15XM,20ХМ,30ХМ,35ХМ,38ХМ,20ХНМ,40ХНМ,20ХГТ,20Г2,40Г2,18ХГ,20ХГМ |
| Other Speical Grades can be customized | |
| Industry | Key Applications Parts | Relevant Standards | Our Advantages |
| General Structural | Square Rectangular Tubes | GB/T 3094,ASTM A500, EN 10210 |
Good Surface,lightweight,precision dimensions (±0.1mm) |
| Automotive and Motorcycle Component | Shock Absorbers，Steering Systems，Thrust Rods | EN 10305-1,JIS G3445, DIN 2391,ASTM A519 |
High fatigue strength,High yield strength,lightweight, precision dimensions (±0.1mm) |
| Engineering and Mining Support | Anchor Bolts,Support Pipes,Hydraulic Props | ASTM A519,DIN 2391, JIS G3441,EN 10297-1, ISO 10799 |
High Strength Yield Strength High Elongation Customization Service – Special steel grades, dimensions and surface treatments available according to project requirements |
| Construction Machinery | Drive shaft sleeves,Gearbox Guide Tubes,Crane Boom Guide Tubes,Excavator Arm Tubes,Loader Frame Tubes,Arctic Low-Temperature Tubes | ASTM A519,DIN 2391, JIS G3445,EN 10210-1, GOST 8733, ASTM A106,ISO 9329 |
ID/OD tolerances of ±0.05mm. Wall thickness uniformity straightness ≤0.5mm/m |
| Fluid Transport Systems | Oil/Gas pipelines,chemical systems,Power/Energy | ASTM A106 Gr.B, EN 10216-2,GOST 8734 |
Eddy Current + Ultrasonic Testing,Hydrostatic Testing |
| High-Pressure Boilers | Superheaters,Steam lines,Reheaters,Economizers) | ASTM A192,DIN 17175, EN 10216, JIS G3461/G3462 |
Enhanced material density through cold-drawing/rolling ensures long-term stability Full Compliance with Int’l Standards,Superior Creep Fatigue Resistance |
| Geological Drilling | Drill Pipe,Tubing | ASTM A519,API 5DP, EN 10208-2 |
High Strength Wear Resistance precision Dimensions Impact Fatigue Resistance |
| Agricultural Machinery | Hydraulic cylinders,drive shafts,Lift arms,steering housings,Boom frames | ASTM A519,EN 10210-1, DIN 2391,GOST 8733, JIS G3445 |
Material Advantages:High Strength Lightweight,Precision Cold-Drawing Technology,Dimensional accuracy ±0.05mm |
| Petroleum Cracking Units | Reformer Tubes,Heat Exchanger Tubes,Reactor Feed Pipes,Transfer Lines,Quench Oil Pipes | ASTM A335,ASTM A213, EN 10216-2 |
Optimized Material Purity,Precision Dimensional Control,Customized Solutions |
Tailored Features · Designed Exclusively for Your Needs
Precision-Engineered Alloy Steel Solutions-20% Cost Efficiency Certified Mill Partnerships:
Collaborating with Baosteel, Xingcheng, and Shagang to deliver:
✔ 100+ Custom Alloy Grades– Chemistry control (C, Cr, Ni, Mo adjustments)
✔ Engineered Mechanical Properties -Yield/Tensile strength customization
✔ Industrial-Grade QC-Full-spectrum testing (UT, hardness, dimensional)
✔ Verified 20% Cost Savings-Through optimized supply chain
Application:Oil & Gas, Automotive, Heavy Machinery, Energy
Extra-Long Piercing + Automated Normalizing Furnace – Precision Alloy Steel Tubes for High-Stress Applications Breakthrough Heating Technology:
Our extra-long piercing furnace ensures uniform heating, of alloy steel billets, eliminating defects like cracks, scaling, and eccentricity for superior tube integrity.p; for precision tubing.
Automated Normalizing Excellence:
✔ ±2°C Precision Control–Industry-leading temperature stability
✔ Enhanced Mechanical Properties–Optimized strength & fatigue resistance
✔ 100% Batch Consistency–Reliable performance for critical applications
Key Industries Served:Oil & Gas, Power Generation, Automotive, Geological Drilling, Mining Support and Construction
Ultra-Precision Tube Straightening – ≤0.5mm/m Tolerance for 30% Faster Machining Industry-Leading Straightening Technology:
Our proprietary system delivers ≤0.5mm/m straightness (4X tighter than standard), enabling:
✔ 30% Faster Machining–Minimizes lathe adjustment time
✔ Extended Tool Life –Reduces cutting tool wear by 20%
✔ Lower Production Costs –Less scrap & downtime
Technical Superiority:
Expert Operation – 20+ years master technicians
Automated QC – Real-time straightness monitoring
Custom Solutions– Optimized for alloy steel grades
Key Applications: Hydraulic Cylinders,Oil & Gas, High-Performance Automotive (drive shafts, suspension components)
Ultrasonic + Eddy Current Dual Testing – High-Reliability Inspection for Alloy Steel Tubes
Advanced NDT System Features:
✔ Ultrasonic Testing (UT)– Detects internal flaws down to 0.20mm
✔ Eddy Current (ET)– Identifies surface/subsurface defects
✔ Multi-Probe Technology– Complete ID/OD/wall coverage
Quality Assurance:
99.7% Detection Rate(Industry-proven reliability)
Dimensional Control– ±0.05mm OD tolerance
Material Verification– Full composition check
Certified Applications: Oil Gas, Energy, Automotive
Annealing represents a crucial delivery condition for precision steel tubes, commercially designated as GBK（+A） condition. Annealed Steel Tubes in GBK condition constitute a specialized category of precision steel pipes that have undergone complete annealing treatment after cold forming processes. These stress-relieved seamless tubes are manufactured accordi
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Cold-Drawn Seamless Steel Pipes, also known as precision-drawn tubes or cold-finished seamless pipes, represent our high-precision product line manufactured through advanced cold-drawing technology. These precision cold-drawn tubes are produced by drawing seamless steel billets through precision dies at room temperature, resulting in superior dimensional acc
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Cold Finished and Stress-Relieved Steel Pipes (BKS/+SR Condition) represent a precision delivery state where steel tubes undergo specialized stress relief annealing after cold forming processes. These stress-relieved seamless tubes effectively eliminate residual internal stresses from cold working while preserving the high dimensional accuracy and partial st
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Cold Finished (hard) Steel Pipes (BK/+C) represent a delivery state where steel tubes undergo cold forming processes without subsequent heat treatment. These hard-condition seamless tubes maintain their as-cold-worked properties, featuring high strength and precise dimensional characteristics that make them suitable for applications requiring rigid component
View product →Tell us the material grade, outer diameter, wall thickness, quantity and end-use requirements.
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