Describe the diameter, thread pitch, or flange spec. ChatMRO finds the exact ASTM-grade match, shows alternatives, and gives you a quote — in seconds. No part number needed.
A double end threaded stud (also called a stud bolt) is a headless fastener threaded on both ends, with a plain or reduced-diameter shank in between. Unlike a conventional bolt, it has no head — two hex nuts (one on each end) clamp the joint together, allowing the stud to stretch elastically along its full length rather than twisting like a bolt shank.
Piping engineers and maintenance teams rely on double end studs for flange connections, pressure vessel closures, valve bonnets, and heavy structural clamping where uniform, repeatable clamp load matters. Their ability to distribute tension evenly across a joint — and to be re-torqued without damaging a bolt head — makes them the standard choice over hex head bolts in nearly all ANSI/ASME flanged piping systems.
Common types: continuous-thread (fully threaded), double-end clamping stud (identical thread length both ends), and tap-end stud (different thread lengths, one end threads into a tapped hole). Common grades: ASTM A193 B7, B7M, B8, B8M, B16; ASTM A320 L7, L7M; ASTM A354; ASTM A307.
Stop second-guessing. Match your use case below — then let ChatMRO's AI surface the exact grade, dimensional data, and alternatives in one natural-language search.
ANSI/ASME B16.5 flanges, valves, and pressure vessel joints. Typically A193 B7 continuous-thread studs with two heavy hex nuts.
Sub-zero process lines, LNG, and refrigeration piping. Impact-tested low-alloy studs dominate here.
Machine mounting, equipment bases, and general-purpose clamping outside pressure-boundary service.
Double end stud bolts are specified by ASTM grade rather than brand, and supplied by fastener manufacturers to full dimensional and material certification. Here's how to navigate grade selection without a 40-tab browser session.
ChatMRO indexes stud bolt inventory across grades and manufacturers. Search any product by description, application, or rough spec.
The piping workhorse. Quenched and tempered Cr-Mo alloy steel, 105 ksi minimum tensile strength (up to 2.5" dia.). UNC/8UN threads, Class 2A fit. Used with A194 2H heavy hex nuts.
Search ASTM A193 Grade B7 →Same base alloy as B7 with mandatory impact testing for sub-zero service. Used on cryogenic and low-temperature process piping. Available in dual-certified B7/L7.
Search ASTM A320 Grade L7 →304 (B8) or 316 (B8M) stainless for corrosive or hygienic environments. Lower strength than B7 but excellent corrosion resistance. Class 1 or Class 2 (strain-hardened) strength options.
Search ASTM A193 Grade B8 / B8M →Use this table as a decision shortcut. Ask ChatMRO for the exact part once you know which row fits your spec.
| Grade | Material | Thread Std | Best For | Tensile Strength | Temp Range | ChatMRO Verdict |
|---|---|---|---|---|---|---|
| ASTM A193 B7 | Cr-Mo alloy steel | UNC / 8UN | General flanges, pressure vessels | 125 ksi (≤2.5" dia.) | -20°F to 1,000°F | Best availability + pricing for standard flanged joints |
| ASTM A320 L7 | Cr-Mo alloy steel, impact-tested | UNC / 8UN | Low-temp and cryogenic piping | 125 ksi | -150°F to 400°F | Required whenever sub-zero service is specified |
| ASTM A193 B8/B8M | 304 / 316 stainless steel | UNC / 8UN | Corrosive, food-grade, hygienic service | 75–100 ksi (Class 1/2) | -325°F to 1,500°F | Best corrosion resistance — verify strength class needed |
| ASTM A453 Grade 660 | Precipitation-hardened SS | UNC / 8UN | High-temperature, thermal cycling service | 130 ksi | Up to 1,200°F | Use when B7 doesn't meet high-temp creep requirements |
| ASTM A354 Grade BD | Quenched & tempered alloy steel | UNC / UNF | Structural and general clamping | 150 ksi | Ambient | Higher strength than A307 for structural bolting |
| ASTM A307 Grade B | Carbon steel | UNC | Low-pressure flanges, general use | 60 ksi | Ambient | Avoid for high-pressure service — use A193 B7 instead |
Not sure which row is yours? Describe your application to ChatMRO and get an instant AI-matched recommendation with datasheets.
Traditional catalogues force you to know the exact MPN before you find anything. ChatMRO flips that: describe what you need in plain English, and the AI finds the right stud bolt from 30M+ indexed parts.
In plain language — by flange size, pressure class, or service temperature. No MPN required.
Natural language processing maps your description to the closest-fit products across grades and specs.
Cross-grade equivalents, lower-cost substitutes, and in-stock alternatives shown side-by-side.
Add to cart or request RFQ directly from the results. No phone calls. No email chains.
Whether you're a piping engineer specifying bolting for a new flange schedule, or a maintenance planner doing an emergency valve rebuild — use this framework before you procure.
Diameter and length are dictated by ANSI/ASME B16.5 or B16.47 flange tables, based on nominal pipe size and pressure class. ChatMRO surfaces the matching stud size and quantity per flange automatically.
A193 B7 covers general high-temperature service; A320 L7 is mandatory for low-temperature/cryogenic lines requiring impact testing. Mixing grades on the same joint creates traceability and code-compliance risk.
Stainless (B8/B8M) or coated studs (Xylan, PTFE) for corrosive or washdown environments. Carbon/alloy steel with zinc or hot-dip galvanizing for general outdoor structural use.
UNC is standard below 1" diameter; 8UN is standard for A193/A320 studs 1" and above. Confirm Class 2A external thread fit matches the mating nut's Class 2B internal thread.
Nut grade must be compatible with the stud grade (e.g., A194 2H with B7, A194 7 with L7). Request mill test reports (3.1/3.2 certification) for pressure-boundary or code-stamped applications.
B7 and L7 studs are often dual-certified and interchangeable in stock — search by function on ChatMRO to surface exact matches AND in-stock substitutes in one step.
Pairing a low-temperature L7 stud with a standard 2H nut (rather than a matching Grade 7 nut) undermines the joint's certified service rating. Confirm the full stud-and-nut set before ordering.
Sour service (H2S-containing) and cryogenic lines require hardness limits and impact testing per NACE MR0175 or A320 respectively. Apply the correct grade rather than defaulting to standard B7.
Describing your application to ChatMRO takes 30 seconds. The AI reads stud bolt spec sheets across grades so you don't have to.
Just describe what you need. ChatMRO finds the right double end threaded stud in seconds.
Double end threaded stud bolts are among the most widely specified fasteners in pressure piping, valve, and pressure vessel construction. ASTM A193 and A320 grades command significant specification share globally due to their proven performance in high-temperature, high-pressure, and low-temperature service, backed by decades of code history under ASME B16.5 and B16.47. Procurement professionals and piping engineers in India, Southeast Asia, and North America regularly source A193 B7, A320 L7, and stainless B8/B8M studs for flange bolting, valve bonnet closures, and structural clamping.
ChatMRO simplifies this procurement process by providing AI-powered natural language search across a catalogue of 30 million+ indexed industrial parts. Engineers and buyers no longer need to memorize grade designations or navigate multi-level filter trees to find the right stud bolt. A simple description of the flange size, pressure class, service temperature, or material requirement is sufficient to surface the correct grade alongside cross-grade alternatives and real-time pricing.