The cold changes everything. In low-temperature and LNG-related applications, ordinary fasteners can lose strength or break suddenly. When flanges have different thread requirements, a simple connection becomes a critical engineering challenge.
L7 Combo Studs address both challenges. They are made from ASTM A320 Grade L7 alloy steel. They retain strength and impact toughness where standard bolting becomes brittle. Their dual-thread design also joins assemblies with different thread forms on each end, with no adapters required.
Clarion delivers the secure, leak-resistant joint your project depends on.
Overview of L7 Combo Studs
L7 Combo Studs are high-strength alloy steel fasteners produced to ASTM A320 Grade L7. They are for dependable bolted connections in low-temperature service. Unlike a conventional all-thread stud, a combo stud carries two different thread configurations on one body, one at each end.
This design suits specialized flange assemblies and mismatched connection requirements. It provides smooth thread engagement, balanced load distribution, and steady clamping force across the joint.
Whether you are building a new system or maintaining existing equipment, we match the material grade, thread type, and length to your project.
Key Features of L7 Combo Studs
Strength with low-temperature toughness
This stud is built for cold-service conditions where brittle failure is a genuine risk.
Precision thread configurations
Each end is machined to the thread type and size your connection calls for.
Dependable joint integrity
Consistent preload keeps flanged joints tight and stable.
Made for demanding environments
Suited to high-pressure, high-stress, and temperature-sensitive service.
Wide material range
ASTM A320 Grade L7 and L43, Stainless Steel 304/316, Duplex, Super Duplex, Inconel, Monel, and other specialty alloys.
Standards and Compatibility
| Parameter | Details |
|---|---|
| Base Specification | ASTM A320 Grade L7 |
| Alternate Grades | ASTM A320 Grade L43, plus stainless, duplex, super duplex, and specialty alloys on request |
| Stud Type | Combo (dual-thread) |
| Compatible Nuts | Typically ASTM A194 Grade 7 or Grade 4; impact-tested Grade 7L where the specification requires it |
| Thread Configuration | Per your drawing, with thread type and size defined for each end |
| Dimensions | Diameter and length built to your specification |
| Low-Temperature Service | Matched to your lowest design metal temperature and project specification |
| Documentation | Material test reports, traceability, and inspection records available on request |
Coating Options
| Coating | Purpose |
|---|---|
| Zinc | General corrosion resistance |
| Black Phosphate | Light corrosion protection with a lubricating surface |
| Black Oxide | Mild corrosion resistance and a uniform finish |
| Cadmium | Corrosion protection, subject to project and regulatory requirements |
| Xylan | Low friction and strong corrosion and chemical resistance, per the selected coating system |
Not sure which coating suits your environment? Share your service conditions, and we will help you choose.
Applications
L7 Combo Studs are used wherever low-temperature performance and secure connections matter, subject to design temperature and service requirements:
LNG-related facilities
Flanged piping and equipment connections in cold service, where the bolting grade meets the design temperature and project specification.
Petrochemical plants
Reliable bolted joints in cold-service process units, heat exchangers, vessels, and piping.
Offshore installations
Dependable low-temperature bolting where corrosion, pressure, and marine exposure raise the demands.
Heat exchangers
Channel covers, shell flanges, and removable heads exposed to low temperatures or thermal cycling.
Pressure vessels
Flanged nozzles, closures, and critical connections in low-temperature pressure-containing equipment.
Compressors
High-strength bolted assemblies that must hold clamping force through vibration, pressure, and temperature swings.
Industrial piping systems
Flange connections in cold process lines where joint integrity and leak prevention are essential. This also includes L7 Combo Studs for Oil and Gas Pipelines.
Why Choose Clarion as Your L7 Stud Bolts Supplier
Clarion Industrial is a Houston-based manufacturer with more than 25 years of experience. It produces studs and precision-engineered components. We build to your drawings and specifications, with inspection, testing, and documentation available as required. You receive the right thread configuration, material, and finish. Backed by the traceability your project demands.
We also supply L7 Combo Studs for Industrial Applications. We supply them across a wide range of sectors. We make them to your print rather than pulling from a catalog.
Request a Quote
L7 Combo Studs from Clarion are made to your specifications. To quote accurately, please send:
- Your drawing or sketch
- Diameter and overall length
- Thread type and size for each end
- Material grade: ASTM A320 Grade L7 (or L43 / alternate alloy)
- Coating requirement
- Lowest design metal temperature and service condition
- Applicable design code or project specification
- Nut and washer requirements
- Quantity and delivery timeline
- Required material test reports, traceability, and inspection documentation
If you don’t have a complete drawing yet? Send your requirements and our team will help you.
Get Your L7 Combo Studs QuoteFrequently Asked Questions
What is the lowest operating temperature for L7 Combo Studs?
ASTM A320 Grade L7 is Charpy-tested at −150°F (−101°C). Colder service requires engineer and project-specification approval.
What strength ratings do L7 Combo Studs carry?
Up to 2½ inches, L7 requires 125 ksi minimum tensile and 105 ksi minimum yield strength. Larger diameters have lower minimums.
Which nuts suit L7 Combo Studs?
ASTM A194 Grade 7 or Grade 4 heavy hex nuts are common. Use impact-tested Grade 7L where cold-service rules require it.
Can I order L7 Combo Studs in other materials?
Yes. Clarion offers L43, Stainless Steel 304/316, Duplex, Super Duplex, Inconel, Monel, and other specialty alloys per requirements.
How do I choose the right coating for L7 Combo Studs?
Choose based on corrosion, friction, torque-tension performance, and regulations. Clarion recommends Zinc, Black Phosphate, Black Oxide, Cadmium, or Xylan.