SWRH 42B Wire Rod
SWRH 42B is a high-carbon spring wire rod per JIS G 3506 with 0.39-0.46% carbon. Diameter 5.5mm to 16mm, spheroidized annealed (HBW 170-230). Primary feedstock for valve springs, suspension springs, and high-performance mechanical springs.
| Material | Carbon Steel (High Carbon Spring Wire Rod) |
|---|---|
| Grade / Standard | SWRH 42B |
| Diameter | 5.5mm - 16mm (Nominal) |
| Delivery Condition | hot_rolled / annealed |
| Surface Treatment | coated |
| MOQ | 5 Tons |
| Delivery Time | 25-40 Days / In Stock |
| Loading Port | Tianjin / Shanghai / Qingdao |
Overview of SWRH 42B Wire Rod
SWRH 42B is a high-carbon wire rod grade specified under Japanese standard JIS G 3506 (High carbon steel wire rods) and represents one of the most widely used raw materials for spring wire manufacturing globally. With controlled carbon content range of 0.39-0.46%, SWRH 42B wire rod is specifically engineered for oil-tempered spring wire production, valve springs, suspension springs, and mechanical springs requiring high fatigue resistance and elastic properties. The grade designation ‘SWRH’ stands for Steel Wire Rod Hard, while ’42B’ indicates the approximate carbon content in hundredths of a percent with ‘B’ denoting boron addition for improved hardenability.
SWRH 42B wire rod offers excellent hardenability and strength after proper heat treatment, with the ability to achieve tensile strength exceeding 1800 MPa in the final oil-tempered wire condition. The rod is typically supplied in spheroidized annealed condition with hardness of 170-230 HBW, optimized for subsequent wire drawing operations requiring significant cross-sectional reduction. After drawing and heat treatment (patenting followed by oil tempering), SWRH 42B produces spring wire with exceptional fatigue life, high yield strength, and excellent dimensional stability under cyclic loading. The grade is the industry standard for automotive valve springs, clutch springs, suspension springs, and high-performance mechanical springs in machinery, aerospace, and industrial applications requiring superior spring performance and reliability.
Key Features and Manufacturing Process
SWRH 42B wire rod is manufactured through precision continuous hot rolling process from high-quality steel billets with strictly controlled chemical composition, followed by controlled cooling and mandatory spheroidize annealing heat treatment to achieve optimal microstructure for wire drawing. The spheroidizing treatment (heating to 680-730°C, holding, and slow cooling) transforms the pearlitic structure to spheroidized cementite in ferrite matrix, reducing hardness to 170-230 HBW and significantly improving cold drawability despite the high carbon content.
The rod is supplied in nominal diameter range from 5.5mm to 16mm, with the most common production sizes being 5.5mm, 6.5mm, 8mm, 10mm, 12mm, and 13mm for spring wire drawing operations. Surface quality is critical for spring applications, with strict requirements for surface decarburization depth (typically ≤0.5% of diameter), freedom from seams, laps, and surface defects that could initiate fatigue cracks. Standard coil weight ranges from 1.5 to 3 tons with internal diameter of 850mm, optimized for high-speed multi-pass wire drawing lines. Each coil is supplied with comprehensive mill test documentation including complete chemical analysis, mechanical properties, spheroidization structure verification (metallographic examination), surface decarburization depth measurement, and heat treatment certification ensuring compliance with stringent spring wire industry requirements.
Main Applications of SWRH 42B Wire Rod
SWRH 42B wire rod is the primary raw material for automotive valve spring wire production, where after drawing to final diameter (typically 2-8mm) and oil tempering heat treatment, it achieves tensile strength of 1600-2000 MPa with exceptional fatigue resistance for engine valve spring applications in gasoline and diesel engines. Automotive suspension spring manufacturing extensively uses SWRH 42B for coil springs in passenger vehicles, light commercial vehicles, and heavy-duty trucks requiring high load capacity and long fatigue life under cyclic loading conditions.
Clutch spring production for automotive transmissions, motorcycle clutches, and industrial clutch assemblies relies on SWRH 42B for its combination of high strength and excellent fatigue properties. The grade is also used for compression springs in machinery equipment, hydraulic systems, pneumatic systems, precision instruments, and industrial assemblies requiring reliable spring performance under continuous cycling. Extension springs and torsion springs for garage doors, agricultural equipment, construction machinery, and industrial applications use SWRH 42B drawn wire. High-performance applications include aerospace springs for landing gear, control systems, and safety-critical components, railway suspension springs for passenger and freight cars, mining equipment springs for heavy-duty applications, and oil field equipment springs requiring corrosion resistance (after appropriate surface treatment). After wire drawing and patenting followed by oil tempering, SWRH 42B produces premium spring wire meeting stringent automotive OEM specifications including SAE J316, SAE J172, and international spring wire standards.
Why Choose Us for SWRH 42B Wire Rod
Shandong Tanglu Metal Material Co., Ltd. supplies premium SWRH 42B wire rod sourced from major Japanese-standard certified Chinese steel mills with advanced production facilities, precise chemical control systems, and comprehensive quality assurance programs specifically designed for spring wire applications. Each coil undergoes mandatory chemical composition analysis with tight control of carbon, silicon, manganese, and critical residual elements, comprehensive mechanical property testing, metallographic examination to verify spheroidization structure (minimum 90% spheroidization ratio), surface decarburization depth measurement using microscopic analysis, and dimensional verification per JIS G 3506 requirements, ensuring consistent wire drawing performance and final spring wire quality.
We offer comprehensive diameter range from 5.5mm to 16mm in spheroidized annealed condition (hardness 170-230 HBW) with flexible coil weight configurations from 1.5 to 3 tons matching various downstream spring wire drawing line specifications. Special surface quality inspection ensures freedom from defects critical for fatigue-sensitive spring applications. With monthly supply capacity of 15,000 tons of wire rod and established export experience to over 50 countries serving spring manufacturers, automotive Tier 1 suppliers, valve spring producers, and specialty wire mills globally, we support both project orders and long-term supply contracts with consistent quality and stable pricing. Each shipment includes original mill test certificate (MTC) conforming to EN 10204 3.1 standard with complete chemical analysis, mechanical properties, and spheroidization verification, with EN 10204 3.2 independent certification and third-party inspection (SGS, BV, Intertek, TÜV, ALS) available for automotive and aerospace applications requiring PPAP documentation and enhanced quality assurance. Our SWRH 42B wire rod meets the stringent requirements of global automotive OEMs and spring manufacturers for consistent performance and reliability.
📐 Dimension & Size Table
| Diameter (mm) | Coil Weight (Ton) | Coil ID (mm) | Weight (kg/m) |
|---|---|---|---|
| 5.5 | 1.5 - 2.5 | 850 | 0.187 |
| 6.0 | 1.5 - 2.5 | 850 | 0.222 |
| 6.5 | 1.5 - 3.0 | 850 | 0.260 |
| 8.0 | 1.8 - 3.0 | 850 | 0.395 |
| 10.0 | 2.0 - 3.0 | 850 | 0.617 |
| 12.0 | 2.0 - 3.0 | 850 | 0.888 |
| 13.0 | 2.0 - 3.0 | 850 | 1.042 |
| 14.0 | 2.0 - 3.0 | 850 | 1.208 |
| 16.0 | 2.0 - 3.0 | 850 | 1.579 |
* Custom sizes available upon request. Tolerances per relevant international standards.
🔬 Chemical Composition
| Element | Min | Max | Display Value | Note |
|---|---|---|---|---|
| C | 0.39 | 0.46 | 0.39-0.46 | Per JIS G 3506 SWRH 42B |
| Si | 0.15 | 0.35 | 0.15-0.35 | Controlled for spring properties |
| Mn | 0.50 | 0.80 | 0.50-0.80 | |
| P | - | 0.030 | ≤0.030 | Strict control for spring wire |
| S | - | 0.030 | ≤0.030 | Strict control for spring wire |
| Cu | - | 0.25 | ≤0.25 | Residual element control |
| Cr | - | 0.20 | ≤0.20 | Unless intentionally added |
| Ni | - | 0.25 | ≤0.25 | Residual element control |
| B | 0.0005 | 0.0030 | 0.0005-0.0030 | Boron for hardenability (optional) |
| Al | - | 0.050 | ≤0.050 | Aluminum killed steel |
* Chemical composition may vary by heat, thickness and specification. Please refer to the actual mill test certificate.
⚙️ Mechanical Properties
| Property | Value | Unit | Test Condition |
|---|---|---|---|
| Tensile Strength (Spheroidized) | 540-680 | MPa | Spheroidized annealed condition |
| Brinell Hardness (Spheroidized) | 170-230 | HBW | After spheroidize annealing for drawability |
| Reduction of Area | ≥40 | % | Wire drawing capability indicator |
| Spheroidization Ratio | ≥90 | % | Metallographic requirement for optimal drawability |
| Surface Decarburization | ≤0.5 | % | Maximum depth as % of diameter (critical for springs) |
| Tensile Strength (After Oil Tempering) | 1600-2000 | MPa | Final spring wire after drawing and heat treatment |
| Spring Wire Hardness (Oil Tempered) | 450-550 | HV | Typical hardness for valve spring wire |
| Wire Drawing Reduction | ≥90 | % | Total area reduction capability with inter-annealing |
| Torsion Test (Final Wire) | ≥18 | turns | For 2mm diameter spring wire (per SAE J172) |
* Values shown are minimum requirements unless otherwise stated.
📦 Commercial Information
| Packaging | Standard seaworthy export packing for high-carbon spring wire rod. Compact coils with 4-6 heavy-duty steel strapping bands per coil to maintain shape during handling and sea transport. Each coil tagged with heat number, grade designation (SWRH 42B / JIS G 3506), nominal diameter, coil weight, heat treatment condition (spheroidized annealed), and hardness range. Coils loaded with vertical eye orientation in container, separated by wooden battens and moisture barrier materials to prevent corrosion during transit. Standard coil dimensions: internal diameter 850mm, outer diameter 1250mm, height 800-1100mm depending on coil weight. For spring wire applications, special protective packaging with VCI (volatile corrosion inhibitor) paper and moisture barrier available. Custom coil weight (1.0-3.5 tons) available to match specific downstream spring wire drawing line specifications and lifting equipment capacity. |
|---|---|
| Payment Terms | T/T (Telegraphic Transfer),L/C (Letter of Credit),D/P (Documents against Payment),Western Union,PayPal |
| Price Term | FOB,CFR,CIF,EXW |
| Supply Capacity | 15,000 Tons/Month (Wire Rod All Grades) |
| Loading Port | Tianjin / Shanghai / Qingdao |
Why Choose Our SWRH 42B Wire Rod?
JIS G 3506 Spring Wire Quality
SWRH 42B wire rod supplied with comprehensive mill test certificate EN 10204 3.1/3.2 meeting JIS G 3506 requirements, including complete chemical composition analysis, mechanical properties verification, metallographic examination confirming ≥90% spheroidization ratio, surface decarburization depth measurement (≤0.5% diameter), and complete heat treatment certification ensuring optimal wire drawing performance and final spring wire quality.
Complete Spring Wire Diameter Range
Diameter range from 5.5mm to 16mm in spheroidized annealed condition covering all standard spring wire drawing requirements. Common sizes include 5.5mm, 6.5mm, 8mm, 10mm, and 12mm for valve spring wire, suspension spring wire, and mechanical spring production.
Superior Spring Performance
High carbon content 0.39-0.46% with controlled silicon 0.15-0.35% and optimized boron addition provides exceptional hardenability and strength. After wire drawing and oil tempering, achieves tensile strength 1600-2000 MPa with excellent fatigue resistance meeting automotive OEM specifications for valve springs and suspension springs.
Automotive Grade Quality Control
Stringent quality control including strict P/S limits (≤0.030% each), surface decarburization control, freedom from surface defects, and metallographic verification. Suitable for automotive Tier 1 suppliers with PPAP documentation and third-party inspection available for critical applications.
Spring Wire Industry Specialist
Extensive experience supplying SWRH 42B to global valve spring manufacturers, automotive suspension spring producers, and specialty spring wire mills. Monthly capacity 15,000 tons with spheroidized annealed condition as standard, ensuring consistent drawability and final spring wire performance.
🏭 Applications of SWRH 42B Wire Rod
SWRH 42B wire rod is the primary raw material for automotive valve spring wire production, where after drawing to final diameter (typically 2-8mm) and oil tempering heat treatment (patenting at 900-950°C followed by quenching in oil at 60-90°C), it achieves tensile strength of 1600-2000 MPa with exceptional fatigue resistance for engine valve spring applications in gasoline and diesel engines. Automotive suspension spring manufacturing extensively uses SWRH 42B for coil springs in passenger vehicles, light commercial vehicles, SUVs, and heavy-duty trucks requiring high load capacity and long fatigue life exceeding 10 million cycles under cyclic loading conditions. Clutch spring production for automotive transmissions, motorcycle clutches, and industrial clutch assemblies relies on SWRH 42B for its combination of high strength, excellent fatigue properties, and consistent heat treatment response. The grade is also used for compression springs in heavy machinery equipment, hydraulic systems, pneumatic systems, precision instruments, and industrial assemblies requiring reliable spring performance under continuous high-stress cycling. Extension springs and torsion springs for garage door systems, agricultural equipment, construction machinery, and industrial applications use SWRH 42B drawn wire. High-performance applications include aerospace springs for landing gear, control systems, and safety-critical components requiring stringent quality documentation, railway suspension springs for passenger and freight cars, mining equipment springs for heavy-duty applications under harsh conditions, and oil field equipment springs requiring both strength and corrosion resistance (with appropriate surface treatment). After wire drawing and heat treatment, SWRH 42B produces premium spring wire meeting SAE J316, SAE J172, EN 10270-1 SH, and international automotive OEM specifications.
📋 Quality & Certification
Our Certifications
- ✅ ISO 9001:2015
- ✅ CE Marking
- ✅ ABS
- ✅ DNV GL
- ✅ Bureau Veritas (BV)
- ✅ SGS Certified
Mill Certificate Type
- 📋 EN 10204 3.1
- 📋 EN 10204 3.2
- 📋 Third Party Inspection Available
- 📋 Certificate of Origin
❓ Frequently Asked Questions
What is SWRH 42B wire rod?
SWRH 42B is a high-carbon spring wire rod grade specified under Japanese standard JIS G 3506 with carbon content range of 0.39-0.46%. The designation 'SWRH' stands for Steel Wire Rod Hard, indicating high-carbon content suitable for spring wire applications. SWRH 42B is specifically engineered for oil-tempered spring wire production, particularly valve springs, suspension springs, and mechanical springs requiring high fatigue resistance and elastic properties. The rod is typically supplied in spheroidized annealed condition with hardness of 170-230 HBW, optimized for multi-pass wire drawing operations. After drawing and heat treatment (patenting followed by oil tempering), SWRH 42B produces spring wire with tensile strength of 1600-2000 MPa, exceptional fatigue life exceeding 10 million cycles, and excellent dimensional stability under cyclic loading conditions.
What is the equivalent grade of SWRH 42B?
SWRH 42B has equivalent grades in multiple international standards: SAE 1042 and AISI 1042 (American standards with approximately 0.40-0.47% carbon), EN C42D / 1.0740 (European standard for medium-high carbon drawing quality), GB 65 or GB 70 (Chinese standards for spring steel), DIN 1654 C45D (German standard), and ASTM A510 1042 (American specification for carbon steel wire rod). These grades share similar chemical composition (approximately 0.39-0.47% C, 0.50-0.80% Mn, 0.15-0.35% Si) and are used for comparable spring wire applications. However, SWRH 42B per JIS G 3506 has particularly strict requirements for phosphorus and sulfur content (≤0.030% each), surface decarburization depth, and spheroidization structure, making it a premium grade for automotive valve spring and suspension spring wire production where fatigue performance is critical.
What is the difference between SWRH 42B and SAE 1018 wire rod?
The key differences are: (1) Carbon content - SWRH 42B has 0.39-0.46% carbon versus SAE 1018 with 0.14-0.20%, making SWRH 42B significantly higher strength for spring applications. (2) Silicon content - SWRH 42B has controlled 0.15-0.35% Si for spring properties versus SAE 1018 with ≤0.15% Si. (3) Delivery condition - SWRH 42B is typically supplied spheroidized annealed (HBW 170-230) as standard for spring wire drawing, while SAE 1018 can be supplied as-rolled or spheroidized for cold heading. (4) Applications - SWRH 42B is used exclusively for high-performance springs (valve springs, suspension springs) requiring tensile strength exceeding 1600 MPa after heat treatment, while SAE 1018 is used for medium-strength fasteners (Grade 5 bolts) and general cold heading applications. (5) Quality requirements - SWRH 42B has stricter limits on P/S (≤0.030% vs. ≤0.040-0.050%), tighter surface decarburization control (≤0.5% vs. ≤1.0%), and mandatory spheroidization structure verification. SWRH 42B costs 20-30% more but enables high-value spring applications.
Why is SWRH 42B supplied in spheroidized annealed condition?
SWRH 42B is supplied in spheroidized annealed condition because the high carbon content (0.39-0.46%) results in very high hardness (>250 HBW) and poor ductility in the as-rolled condition, making wire drawing extremely difficult or impossible without intermediate annealing. Spheroidize annealing heat treatment (heating to 680-730°C just below the lower critical temperature A1, holding for extended time, and slow cooling) transforms the hard lamellar pearlite microstructure into soft spheroidized cementite particles dispersed in ferrite matrix. This reduces hardness to 170-230 HBW and significantly improves ductility and reduction of area to ≥40%, enabling multi-pass wire drawing with total area reduction exceeding 90%. The spheroidized structure also provides uniform hardness and microstructure throughout the wire rod, ensuring consistent wire drawing forces, reduced die wear, and freedom from wire breaks during high-speed drawing operations. Most spring wire manufacturers require minimum 90% spheroidization ratio verified by metallographic examination as a quality acceptance criterion.
What heat treatment is required to make spring wire from SWRH 42B?
The typical process to produce oil-tempered spring wire from SWRH 42B is: (1) Wire drawing - multiple passes from rod diameter (typically 5.5-13mm) to final spring wire diameter (typically 1.5-8mm) with intermediate annealing if required for large reductions, (2) Patenting - austenizing at 900-950°C followed by rapid cooling (lead bath quenching or controlled air cooling) to transform the structure to fine pearlite, which provides uniform microstructure and improved subsequent tempering response, (3) Oil tempering - reheating to 350-500°C (temperature depends on desired final hardness) and quenching in oil at 60-90°C to achieve final mechanical properties with tensile strength typically 1600-2000 MPa and hardness 450-550 HV, (4) Optional straightening and stress relieving at 200-300°C for dimensional accuracy. This heat treatment sequence is specified in standards such as SAE J172 (Oil Tempered Carbon and Alloy Steel Valve Spring Quality Wire and Springs) and produces spring wire with exceptional fatigue resistance, high yield strength (typically 80-90% of tensile strength), and excellent elastic properties for demanding spring applications.
What are the typical applications of SWRH 42B spring wire?
SWRH 42B spring wire is used in critical applications requiring high strength and fatigue resistance: (1) Automotive valve springs - engine valve springs for gasoline and diesel engines operating at high temperatures and frequencies up to 6000 rpm, requiring fatigue life exceeding 10 million cycles and meeting OEM specifications, (2) Automotive suspension springs - coil springs for passenger cars, SUVs, light trucks, and heavy-duty vehicles requiring high load capacity and long service life, (3) Clutch springs - automotive transmission clutches, motorcycle clutches, and industrial clutch assemblies, (4) Compression springs - heavy-duty industrial springs in machinery, hydraulic systems, pneumatic equipment, safety valves, and precision instruments, (5) Extension and torsion springs - garage door springs, agricultural equipment, construction machinery requiring reliable cyclic performance, (6) High-performance applications - aerospace landing gear springs, railway suspension springs, mining equipment springs, and oil field equipment springs. After proper heat treatment, SWRH 42B spring wire meets SAE J316 (Cold Drawn Wire for Coil Springs), SAE J172 (Valve Spring Quality Wire), EN 10270-1 SH, and automotive OEM specifications from major manufacturers globally.
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