TR_STS_BISECT_10000
The TR-STS is TORCHMARK's general-purpose threaded stud bolt designed for permanent or repeatedly disassembled joints in flanges, pressure vessels, structural assemblies, machinery casings and anchor points. A stud bolt is headless, with machine threads on both ends and a smooth (or partially smooth) shank in the middle — the geometry that lets a nut come down from each side, equalising clamping force around the joint and removing the need for a nut-side access. For a procurement or sourcing team, that geometry is the single biggest reason you specify a stud instead of a hex bolt or a length of threaded rod.
Manufacturing stays in our home factory in Yuyao / Ningbo, Zhejiang, with CNC thread rolling, in-line induction heat treatment (for the alloy-steel grades), automated optical thread gauging and a 100% dimensional sampling station before packing. Every batch ships with a mill test certificate (EN 10204 3.1) and is fully traceable back to the heat of steel. We routinely run OEM / ODM programs for industrial fastener distributors, valve and flange makers, marine hardware brands and construction-supply wholesalers — including private-label retail boxes, custom thread geometry, custom plating and tailored mill cert layout.
Why B2B Buyers Specify Stud Bolts Instead of Hex Bolts
Three procurement scenarios consistently drive our TR-STS orders:
- Flanged joints on pressure equipment. When you have a pipe flange, valve body, heat-exchanger head or pump casing, the bolt circle is often blind on one side or sits in a recess where you cannot swing a wrench over a hex head. A stud threaded into a tapped hole on one flange and a nut on the other is the standard connection — and it lets you tension both sides evenly with a torque wrench on the nut only, which makes field service faster and safer.
- Joints that have to come apart regularly. Studs with two nuts are easier to remove than through-bolted hex fasteners because there is no head to unscrew. For maintenance-heavy equipment — pumps, mixers, gearboxes, hydraulic manifolds — TR-STS reduces mean time to repair.
- Anchor bolts and tie-downs. Concrete-set anchors and structural tie-downs use studs because the embed end is grouted or epoxied, with the exposed thread receiving a heavy nut and washer. The TR-STS is dimensionally compatible with our J-anchor / L-anchor / sleeve-anchor accessory families.
For OEM distributors and wholesalers, this translates into a stable demand pattern: studs sell where the joint is engineered, not where the fastener is generic. Catalogue customers tend to order by diameter, length and grade; project customers (refineries, shipyards, wind farms) order by ASTM grade + thread spec + MTC — our sales and packing workflow is tuned for both.
Common Material Grades We Stock
Each grade addresses a different service environment. We list the actual mechanical limits (as published by the issuing standards body) so your engineering review can quote them directly into your drawings or data sheets.
ASTM A193 — alloy and stainless grades for high-temperature / pressure service
ASTM A193 is the U.S. standard for alloy-steel and stainless-steel bolting for pressure vessels, valves, flanges and fittings for high-temperature or high-pressure service. The four grades we stock most often:
- B7 — quenched-and-tempered chromium-molybdenum alloy steel, the workhorse grade for refineries, petrochemical plants and steam systems up to about 450°C (840°F). Tensile strength ≥ 860 MPa, yield ≥ 720 MPa, hardness HRC 22–32. Comes zinc-plated, hot-dip galvanised or black.
- B8 — AISI 304 stainless, solution-annealed and strain-hardened. General corrosion-resistant service, food equipment, water systems. Tensile ≥ 700 MPa (Class 1) or ≥ 860 MPa (Class 2).
- B8M — AISI 316 stainless, for marine, offshore and chemical service where chloride pitting is a concern. Tensile ≥ 700 MPa (Class 1) or ≥ 860 MPa (Class 2).
- B16 — chromium-moly-vanadium alloy steel, rated for high-temperature service up to about 600°C (1,110°F) — used in turbine casings and high-pressure boiler flanges. Tensile ≥ 860 MPa, yield ≥ 725 MPa, hardness HRC 26–34.
ISO 898-1 / DIN 976 — metric property classes for general structural use
ISO 898-1 is the European property-class standard for bolts, screws and studs made of carbon or alloy steel. The class number follows a load / 100 convention (a 10.9 stud has a tensile of 1,000 MPa).
- Grade 8.8 — medium-carbon steel, quenched and tempered. Tensile ≥ 800 MPa, yield ≥ 640 MPa. The most-used structural grade worldwide.
- Grade 10.9 — alloy steel, quenched and tempered. Tensile ≥ 1,000 MPa, yield ≥ 900 MPa. Used for high-strength structural connections, mining equipment, automotive chassis.
- Grade 12.9 — alloy steel, quenched and tempered. Tensile ≥ 1,220 MPa, yield ≥ 1,100 MPa, HRC 39–44. Reserved for critical or safety-critical joints (lifting gear, vehicle suspension, machine tools).
ASTM A307 — Grade A for general-purpose low-carbon applications
ASTM A307 Grade A covers low-carbon steel bolts and studs for general service where high strength is not required — anchor bolts, pipe flange connections at low pressure, structural tie-downs. Tensile ≥ 415 MPa. Commonly zinc-plated or hot-dip galvanised.
Thread Geometry and Diameter Range
TR-STS is rolled — not cut — on CNC thread rollers from certified wire rod. Rolling produces continuous, mirror-finish thread flanks with a compressed grain structure, raising fatigue life by roughly 30% versus a cut thread of the same nominal size.
Thread systems we stock
- UNC (Unified National Coarse) — e.g. 1/2″-13, 3/4″-10. The default imperial coarse thread per ASME B1.1.
- UNF (Unified National Fine) — e.g. 1/2″-20, 3/4″-16. Used where vibration or fine adjustment is a concern. ASME B1.1.
- Metric Coarse (M) — e.g. M12×1.75, M16×2.0, M20×2.5. ISO 261 / ISO 965-1. The default for ISO 898-1 grades 8.8 / 10.9 / 12.9.
- Metric Fine (MF) — e.g. M12×1.5, M16×1.5, M20×1.5. ISO 261 / ISO 965-1. For thin-wall joints, vibration service or where fine adjustment is required.
Other thread systems on request: BSW (British Standard Whitworth), BSF (British Standard Fine), BA, and limited ACME. Custom thread pitches — left-hand, extra-long-engagement, double-thread — are quoted per drawing.
Diameter and length coverage
Diameter range: M6 / M8 / M10 / M12 / M16 / M20 / M24 / M27 / M30 / M33 / M36 / M42 / M48 / M56 / M64 for metric; equivalent inch sizes 1/4″ / 5/16″ / 3/8″ / 7/16″ / 1/2″ / 5/8″ / 3/4″ / 7/8″ / 1″ / 1-1/8″ / 1-1/4″ / 1-3/8″ / 1-1/2″ / 1-3/4″ / 2″ stocked.
Standard stocked lengths: 40 / 50 / 60 / 70 / 80 / 100 / 120 / 150 / 180 / 200 / 250 / 300 mm. Custom lengths quoted per RFQ.
For inch series, equivalent lengths are 1-1/2″ through 12″. Both cut-to-length CNC and pre-cut bar stock are available; OEM programs with custom thread run-out and chamfer geometry run on our four-axis CNC lathes.
Surface Finish Options
Surface finish is one of the main levers for cost-vs-service-life. We default to plain black (as-rolled, oiled) for indoor structural use, and apply a finish when the service environment demands it.
- Plain black (as-rolled, oiled) — the cheapest. Indoor structural service, low humidity.
- Zinc-plated (electroplated, 5–8 µm) — neutral indoor / sheltered-outdoor service. Salt spray life 48 h NSS to ASTM B117. Default for retail packs.
- Hot-dip galvanised (HDG, 50–80 µm) — outdoor structural, road and bridge work. Salt spray life ≥ 500 h NSS to ASTM B117.
- Mechanical zinc (8–12 µm) + trivalent chromate — RoHS-compliant zinc for European retail and electrical equipment.
- PTFE / Xylan / PTFE-black — for chemical service and threaded connections where galling or sticking after heat is a concern.
- Black oxide (gun finish) — for appearance-sensitive products; minimal corrosion resistance, used with oil coating.
- Yellow zinc / olive zinc — small quantities for colour-matching on-site repair kits.
For marine / offshore service we recommend HDG or 316 (B8M) stainless. For chemical / sour service (NACE MR0175) we can supply H₂S-resistant grades on request.
Mechanical Properties We Test, Per Lot
Every production lot is sampled and tested before the MTC is signed. The test panel below is the default programme for our B7 / 10.9 / 12.9 / B8M batches; reduced test panels available on request for A307-A or low-risk stud programmes.
Hardness
Rockwell C on the shank, mid-length. Target windows: B7 = HRC 22–32, 10.9 = HRC 26–34, 12.9 = HRC 39–44. For each lot we report three points — both ends and centre — plus a hardness survey if specified.
Tensile
Full-section tensile on a CNC-machined specimen per ASTM A370 / ISO 6892-1. Targets: B7 ≥ 860 MPa, 10.9 ≥ 1,040 MPa, 12.9 ≥ 1,220 MPa. We also report elongation and reduction of area.
Salt spray
The TR-STS is TORCHMARK's general-purpose threaded stud bolt designed for permanent or repeatedly disassembled joints in flanges, pressure vessels, structural assemblies, machinery casings and anchor points. A stud bolt is headless, with machine threads on both ends and a smooth (or partially smooth) shank in the middle — the geometry that lets a nut come down from each side, equalising clamping force around the joint and removing the need for a nut-side access. For a procurement or sourcing team, that geometry is the single biggest reason you specify a stud instead of a hex bolt or a length of threaded rod.
Manufacturing stays in our home factory in Yuyao / Ningbo, Zhejiang, with CNC thread rolling, in-line induction heat treatment (for the alloy-steel grades), automated optical thread gauging and a 100% dimensional sampling station before packing. Every batch ships with a mill test certificate (EN 10204 3.1) and is fully traceable back to the heat of steel. We routinely run OEM / ODM programs for industrial fastener distributors, valve and flange makers, marine hardware brands and construction-supply wholesalers — including private-label retail boxes, custom thread geometry, custom plating and tailored mill cert layout.
Why B2B Buyers Specify Stud Bolts Instead of Hex Bolts
Three procurement scenarios consistently drive our TR-STS orders:
Flanged joints on pressure equipment. When you have a pipe flange, valve body, heat-exchanger head or pump casing, the bolt circle is often blind on one side or sits in a recess where you cannot swing a wrench over a hex head. A stud threaded into a tapped hole on one flange and a nut on the other is the standard connection — and it lets you tension both sides evenly with a torque wrench on the nut only, which makes field service faster and safer.
Joints that have to come apart regularly. Studs with two nuts are easier to remove than through-bolted hex fasteners because there is no head to unscrew. For maintenance-heavy equipment — pumps, mixers, gearboxes, hydraulic manifolds — TR-STS reduces mean time to repair.
Anchor bolts and tie-downs. Concrete-set anchors and structural tie-downs use studs because the embed end is grouted or epoxied, with the exposed thread receiving a heavy nut and washer. The TR-STS is dimensionally compatible with our J-anchor / L-anchor / sleeve-anchor accessory families.
For OEM distributors and wholesalers, this translates into a stable demand pattern: studs sell where the joint is engineered, not where the fastener is generic. Catalogue customers tend to order by diameter, length and grade; project customers (refineries, shipyards, wind farms) order by ASTM grade + thread spec + MTC — our sales and packing workflow is tuned for both.
Common Material Grades We Stock
Each grade addresses a different service environment. We list the actual mechanical limits (as published by the issuing standards body) so your engineering review can quote them directly into your drawings or data sheets.
ASTM A193 — alloy and stainless grades for high-temperature / pressure service
ASTM A193 is the U.S. standard for alloy-steel and stainless-steel bolting for pressure vessels, valves, flanges and fittings for high-temperature or high-pressure service. The four grades we stock most often:
B7 — quenched-and-tempered chromium-molybdenum alloy steel, the workhorse grade for refineries, petrochemical plants and steam systems up to about 450°C (840°F). Tensile strength ≥ 860 MPa, yield ≥ 720 MPa, hardness HRC 22–32. Comes zinc-plated, hot-dip galvanised or black.
B8 — AISI 304 stainless, solution-annealed and strain-hardened. General corrosion-resistant service, food equipment, water systems. Tensile ≥ 700 MPa (Class 1) or ≥ 860 MPa (Class 2).
B8M — AISI 316 stainless, for marine, offshore and chemical service where chloride pitting is a concern. Tensile ≥ 700 MPa (Class 1) or ≥ 860 MPa (Class 2).
B16 — chromium-moly-vanadium alloy steel, rated for high-temperature service up to about 600°C (1,110°F) — used in turbine casings and high-pressure boiler flanges. Tensile ≥ 860 MPa, yield ≥ 725 MPa, hardness HRC 26–34.
ISO 898-1 / DIN 976 — metric property classes for general structural use
ISO 898-1 is the European property-class standard for bolts, screws and studs made of carbon or alloy steel. The class number follows a load / 100 convention (a 10.9 stud has a tensile of 1,000 MPa).
Grade 8.8 — medium-carbon steel, quenched and tempered. Tensile ≥ 800 MPa, yield ≥ 640 MPa. The most-used structural grade worldwide.
Grade 10.9 — alloy steel, quenched and tempered. Tensile ≥ 1,000 MPa, yield ≥ 900 MPa. Used for high-strength structural connections, mining equipment, automotive chassis.
Grade 12.9 — alloy steel, quenched and tempered. Tensile ≥ 1,220 MPa, yield ≥ 1,100 MPa, HRC 39–44. Reserved for critical or safety-critical joints (lifting gear, vehicle suspension, machine tools).
ASTM A307 — Grade A for general-purpose low-carbon applications
ASTM A307 Grade A covers low-carbon steel bolts and studs for general service where high strength is not required — anchor bolts, pipe flange connections at low pressure, structural tie-downs. Tensile ≥ 415 MPa. Commonly zinc-plated or hot-dip galvanised.
Thread Geometry and Diameter Range
TR-STS is rolled — not cut — on CNC thread rollers from certified wire rod. Rolling produces continuous, mirror-finish thread flanks with a compressed grain structure, raising fatigue life by roughly 30% versus a cut thread of the same nominal size.
Thread systems we stock
UNC (Unified National Coarse) — e.g. 1/2″-13, 3/4″-10. The default imperial coarse thread per ASME B1.1.
UNF (Unified National Fine) — e.g. 1/2″-20, 3/4″-16. Used where vibration or fine adjustment is a concern. ASME B1.1.
Metric Coarse (M) — e.g. M12×1.75, M16×2.0, M20×2.5. ISO 261 / ISO 965-1. The default for ISO 898-1 grades 8.8 / 10.9 / 12.9.
Metric Fine (MF) — e.g. M12×1.5, M16×1.5, M20×1.5. ISO 261 / ISO 965-1. For thin-wall joints, vibration service or where fine adjustment is required.
Other thread systems on request: BSW (British Standard Whitworth), BSF (British Standard Fine), BA, and limited ACME. Custom thread pitches — left-hand, extra-long-engagement, double-thread — are quoted per drawing.
Diameter and length coverage
Diameter range: M6 / M8 / M10 / M12 / M16 / M20 / M24 / M27 / M30 / M33 / M36 / M42 / M48 / M56 / M64 for metric; equivalent inch sizes 1/4″ / 5/16″ / 3/8″ / 7/16″ / 1/2″ / 5/8″ / 3/4″ / 7/8″ / 1″ / 1-1/8″ / 1-1/4″ / 1-3/8″ / 1-1/2″ / 1-3/4″ / 2″ stocked.
Standard stocked lengths: 40 / 50 / 60 / 70 / 80 / 100 / 120 / 150 / 180 / 200 / 250 / 300 mm. Custom lengths quoted per RFQ.
For inch series, equivalent lengths are 1-1/2″ through 12″. Both cut-to-length CNC and pre-cut bar stock are available; OEM programs with custom thread run-out and chamfer geometry run on our four-axis CNC lathes.
Surface Finish Options
Surface finish is one of the main levers for cost-vs-service-life. We default to plain black (as-rolled, oiled) for indoor structural use, and apply a finish when the service environment demands it.
Plain black (as-rolled, oiled) — the cheapest. Indoor structural service, low humidity.
Zinc-plated (electroplated, 5–8 µm) — neutral indoor / sheltered-outdoor service. Salt spray life 48 h NSS to ASTM B117. Default for retail packs.
Hot-dip galvanised (HDG, 50–80 µm) — outdoor structural, road and bridge work. Salt spray life ≥ 500 h NSS to ASTM B117.
Mechanical zinc (8–12 µm) + trivalent chromate — RoHS-compliant zinc for European retail and electrical equipment.
PTFE / Xylan / PTFE-black — for chemical service and threaded connections where galling or sticking after heat is a concern.
Black oxide (gun finish) — for appearance-sensitive products; minimal corrosion resistance, used with oil coating.
Yellow zinc / olive zinc — small quantities for colour-matching on-site repair kits.
For marine / offshore service we recommend HDG or 316 (B8M) stainless. For chemical / sour service (NACE MR0175) we can supply H₂S-resistant grades on request.
Mechanical Properties We Test, Per Lot
Every production lot is sampled and tested before the MTC is signed. The test panel below is the default programme for our B7 / 10.9 / 12.9 / B8M batches; reduced test panels available on request for A307-A or low-risk stud programmes.
Hardness
Rockwell C on the shank, mid-length. Target windows: B7 = HRC 22–32, 10.9 = HRC 26–34, 12.9 = HRC 39–44. For each lot we report three points — both ends and centre — plus a hardness survey if specified.
Tensile
Full-section tensile on a CNC-machined specimen per ASTM A370 / ISO 6892-1. Targets: B7 ≥ 860 MPa, 10.9 ≥ 1,040 MPa, 12.9 ≥ 1,220 MPa. We also report elongation and reduction of area.
