MSS SP-43 Stainless Steel Buttweld Fittings
MSS SP-43 SS BW Fittings : Specifications | Materials | Dimensions | Weight Chart | Tolerances | FAQ
Leading Manufacturer & Exporter of MSS SP-43 Stainless Steel Buttweld Fittings – Light-Wall Elbows, Tees, Reducers & Caps – Designed for Corrosion-Resistant Low-Pressure Piping – Sizes ½”–24” – Supplying to USA, UK, Germany, UAE & Australia.
Best Export Prices: sales@midlandforgefittings.com
Midland Forge and Fittings follows a strong engineering approach: every MSS SP-43 SS Buttweld Fitting undergoes metallurgical analysis, CAD modeling, precision forming, and non-destructive testing to ensure corrosion resistance and accurate dimensions for low-pressure systems.
We act as a technical partner to EPC contractors and plant operators worldwide, offering traceable production, mill-test certifications, and rapid logistics. Our flexible manufacturing ensures customized quantities and timely delivery to projects across the USA, Germany, UAE, Australia, and beyond.
MSS SP-43 stainless steel buttweld fittings are precision-engineered for light-wall, corrosion-resistant piping systems where weight savings and durability are critical. Manufactured in elbows, tees, reducers, and end caps, these fittings meet the strict dimensional and material requirements of the MSS SP-43 standard, ensuring reliable performance in chemical processing, food-grade lines, desalination plants, and low-pressure marine applications.
Our manufacturing strategy centers on continuous research and process optimization. We invest in automated forming equipment, real-time dimensional scanning, and metallurgy labs that allow rapid adaptation to unique alloy requirements. This emphasis on data-driven production means every MSS SP-43 fitting leaves our facility with verified consistency in grain structure, weldability, and light-wall integrity—critical for long service life in specialized piping networks.
Beyond technical excellence, we integrate sustainable practices into every stage of operations. Recyclable stainless feedstock, energy-efficient furnaces, and closed-loop water systems reduce our environmental footprint while keeping material properties uncompromised. Dedicated engineering liaisons work directly with client design teams, translating project specifications into manufacturable solutions and ensuring that our fittings arrive site-ready for immediate installation.
MSS SP-43 SS Buttweld Fittings
A403 Buttweld Fittings - Materials, Grades & Standards
| Material Category | MSS Standard | Grade / Type | Typical Applications | Features / Notes |
|---|---|---|---|---|
| Stainless Steel | MSS SP-43 | WP304 | Chemical, food-grade, low-pressure pipelines | Corrosion-resistant, weldable, durable |
| Stainless Steel | MSS SP-43 | WP304L | Sanitary, low-temperature applications | Low carbon, corrosion-resistant, dimensionally stable |
| Stainless Steel | MSS SP-43 | WP316 | Marine, chemical, pharmaceutical piping | Excellent corrosion resistance, high strength |
| Stainless Steel | MSS SP-43 | WP316L | Low-temperature, corrosive environments | Low carbon, weldable, resistant to pitting corrosion |
| Stainless Steel | MSS SP-43 | WP321 | High-temperature chemical and process piping | Stabilized stainless, prevents carbide precipitation |
| Stainless Steel | MSS SP-43 | WP347 | Corrosive industrial applications | Stabilized stainless, excellent intergranular corrosion resistance |
MSS SP-43 SS Buttweld Fittings– Size Range & Dimensions
| NPS (Inch) | Outside Diameter (OD, mm) |
Center-to-End / Length (mm) |
Bend Radius (mm) |
Wall Thickness (mm) |
Common Pipe Schedule |
|---|---|---|---|---|---|
| ½” | 21.3 | 42.9 | 25 | 2.77 | Sch 10S |
| ¾” | 26.7 | 48.3 | 32 | 2.87 | Sch 10S |
| 1″ | 33.4 | 57.2 | 40 | 3.38 | Sch 10S |
| 1½” | 48.3 | 76.2 | 65 | 3.68 | Sch 10S |
| 2″ | 60.3 | 89.0 | 75 | 3.91 | Sch 10S |
| 3″ | 88.9 | 114.3 | 100 | 4.78 | Sch 10S |
| 4″ | 114.3 | 139.7 | 125 | 5.49 | Sch 10S |
| 6″ | 168.3 | 190.5 | 150 | 6.55 | Sch 10S |
| 8″ | 219.1 | 228.6 | 200 | 7.11 | Sch 10S |
| 10″ | 273.0 | 292.1 | 250 | 7.92 | Sch 10S |
| 12″ | 323.9 | 330.2 | 300 | 8.56 | Sch 10S |
| 14″ | 355.6 | 368.3 | 350 | 9.27 | Sch 10S |
| 16″ | 406.4 | 419.1 | 400 | 9.53 | Sch 10S |
| 18″ | 457.2 | 470.0 | 450 | 10.31 | Sch 10S |
| 20″ | 508.0 | 520.0 | 500 | 10.97 | Sch 10S |
| 24″ | 609.6 | 620.0 | 600 | 11.13 | Sch 10S |
MSS SP-43 Fittings– Weight Chart
| NPS (Inch) | Elbow 45° (kg) | Elbow 90° (kg) | Tee (kg) | Reducer (kg) | End Cap (kg) | Wall Thickness (mm) |
|---|---|---|---|---|---|---|
| ½” | 0.15 | 0.20 | 0.25 | 0.18 | 0.10 | 2.77 |
| ¾” | 0.22 | 0.28 | 0.35 | 0.26 | 0.15 | 2.87 |
| 1″ | 0.35 | 0.45 | 0.55 | 0.42 | 0.22 | 3.38 |
| 1½” | 0.60 | 0.75 | 0.95 | 0.70 | 0.40 | 3.68 |
| 2″ | 0.90 | 1.15 | 1.40 | 1.05 | 0.65 | 3.91 |
| 3″ | 1.85 | 2.30 | 2.80 | 2.05 | 1.20 | 4.78 |
| 4″ | 3.10 | 3.85 | 4.65 | 3.40 | 2.05 | 5.49 |
| 6″ | 6.50 | 8.00 | 9.50 | 7.00 | 4.10 | 6.55 |
| 8″ | 10.50 | 13.00 | 15.50 | 11.00 | 6.50 | 7.11 |
| 10″ | 17.50 | 21.50 | 25.50 | 18.50 | 11.00 | 7.92 |
| 12″ | 26.00 | 31.50 | 37.00 | 27.00 | 16.00 | 8.56 |
| 14″ | 33.50 | 40.50 | 48.00 | 35.00 | 21.50 | 9.27 |
| 16″ | 42.50 | 51.50 | 60.00 | 44.00 | 28.00 | 9.53 |
| 18″ | 53.00 | 64.00 | 75.00 | 55.00 | 36.00 | 10.31 |
| 20″ | 65.50 | 79.00 | 92.00 | 67.50 | 45.00 | 10.97 |
| 24″ | 95.00 | 115.00 | 135.00 | 100.00 | 65.00 | 11.13 |
Buttweld Fittings - Tolerances as per MSS SP-43
| Parameter | Tolerance / Allowance | Notes / References |
|---|---|---|
| Outside Diameter (OD) | ±0.8 mm (≤ 12” NPS), ±1.6 mm (> 12” NPS) | Ensures proper fit with corresponding pipe |
| Wall Thickness | ±12.7% for smaller sizes, ±3.2 mm for larger sizes | As per MSS SP-43 and ASTM standards |
| Center-to-End / Length | ±1.5% of nominal length | Applies to elbows, tees, and reducers |
| Bend Radius (for elbows) | ±3% of nominal radius | Long-radius and short-radius elbows |
| Concentricity (reducers) | ±1% of nominal OD | Ensures proper alignment in pipeline |
| Angle (elbows) | ±2° | Applies to 45° and 90° elbows |
| End Preparation | ±1 mm bevel length | For butt-weld preparation |
How does MSS SP-43 define wall thickness for fittings?
- MSS SP-43 specifies light-wall thickness for all fittings, optimized for low-pressure systems.
- Wall thickness is correlated with nominal pipe size (NPS) to ensure structural integrity.
- Typical tolerances: ±12.7% for small sizes (≤ 4″), ±3.2 mm for larger sizes (> 12″).
- This ensures compatibility with corresponding pipe schedules while keeping fittings lightweight.
- Wall thickness affects weld penetration, corrosion allowance, and pressure rating, which is critical in chemical and marine applications.
What inspection and testing standards apply to MSS SP-43 fittings?
- Each fitting undergoes dimensional verification per MSS SP-43 tolerances.
- Non-destructive testing (NDT), such as dye penetrant or radiography, checks for weld and material defects.
- Mechanical property tests ensure compliance with tensile strength, yield strength, and elongation requirements.
- Chemical analysis confirms the stainless steel composition matches the designated grade (WP304, WP316, etc.).
- Test reports and Mill Test Certificates (MTCs) provide full traceability for quality assurance.
How are elbows manufactured under MSS SP-43 standards?
- Elbows are produced through cold or hot forming to achieve precise bend radii.
- Long-radius elbows provide smoother fluid flow and lower pressure drop; short-radius elbows are compact for space-constrained installations.
- Post-forming, stress-relief heat treatment ensures dimensional stability and prevents residual stress cracking.
- Ends are beveled for accurate butt-weld connections, maintaining proper alignment with pipes.