Guides / Process

Welding Inconel: What Buyers Should Know Before Specifying It

August 16, 2026

Most buyers who come to us with a machining RFQ are not thinking about welding at all, until the part turns out to be a welded sub-assembly rather than a single piece of solid stock. Inconel behaves differently under a torch than under a cutter, and the differences change which shops can quote the job.

Why 625 and 718 are not the same welding job

Inconel 625 is a solid-solution alloy. It gets its strength from the elements dissolved in the nickel matrix, not from a heat treatment cycle after welding. That makes it generally considered more forgiving to weld than 718, since there is no aging reaction competing with the weld cooling for the same material.

Inconel 718 is age-hardenable. Left unmanaged, the heat of welding can trigger a hardening reaction in the heat-affected zone before the joint has a chance to relax, a failure mode usually described as strain-age cracking. Shops that weld 718 regularly manage this with controlled heat input, sometimes a post-weld solution anneal, and filler metal chosen specifically to reduce the alloy’s sensitivity to it. None of this means 718 cannot be welded. It means the process needs more care and a shop that has actually done it before.

Processes typically used on nickel alloys

Gas tungsten arc welding (GTAW, also called TIG) is the process most commonly associated with nickel superalloys, since it gives close control over heat input and weld pool, which matters more on Inconel than on steel. Some shops also use other processes depending on joint thickness and part geometry. Which process is used, and how well, comes down to the individual shop’s equipment and experience, not something inherent to the alloy. Ask the shop what it runs rather than assuming.

Filler metal has to match the base alloy family

Filler choice is not a minor detail on nickel alloys. A filler that does not match the base metal’s alloy family can leave a joint with lower corrosion resistance or strength than the parent material, even if the weld looks sound. This matters more on Inconel than on carbon steel because the alloying elements that give Inconel its properties, chromium, molybdenum, niobium, are exactly what a mismatched filler can get wrong. A shop that runs nickel alloys routinely will already know which filler goes with which base metal. It is a reasonable question to ask on a quote call regardless.

Tell us about the weld on the RFQ

If your part includes a welded joint, note it explicitly when you send the drawing. Some shops that machine Inconel well do not weld it, or weld other alloys but not nickel. Flagging this up front means we match the RFQ with shops that can actually do both operations, or that manage the weld through a process they already run, instead of a shop that has to figure it out after accepting the job. It also helps to say whether the weld is structural, pressure-boundary, or cosmetic, since that changes what inspection the shop should plan for.

Inspection is worth asking about, not assuming

Dye penetrant inspection is a common way to catch surface-breaking cracks or porosity on a finished weld. Radiography is common where a joint’s internal soundness matters and the geometry allows it. Which of these applies, and to what acceptance criteria, depends on your spec, your industry, and sometimes your customer’s own requirements. We do not run inspection ourselves. What we can do is pass your requirement along clearly so the shop you get matched with can confirm it can meet it before it quotes the job.

How a welded joint changes the quote

A welded sub-assembly typically adds more to a quote than the weld pass itself. Post-weld solution annealing, where used, is a separate furnace cycle with its own handling and fixturing. Inspection, if your spec calls for dye penetrant or radiography, is a separate step with its own turnaround time, sometimes performed by a third party rather than the machining shop itself. Machining that has to happen after welding, to bring a joint back to final dimension once distortion from heat input is accounted for, also takes longer than the same feature cut on solid stock. None of this means a welded part is a bad idea. It means the quote reflects real steps, and a shop that has priced this before will break the number down instead of treating it as a single line.

What a buyer can control

A few choices on your end make the welded joint easier and cheaper to quote well. Locating the weld away from a feature that needs tight tolerance reduces how much post-weld machining has to correct for distortion. Specifying inspection only where the joint is actually structural or pressure-bearing, rather than applying the same requirement across a whole assembly, keeps cost proportional to risk. And sending the drawing with the weld joint clearly called out, rather than leaving it to be inferred from a multi-part assembly drawing, means the shop prices what you actually need the first time.

If your part has a welded sub-assembly, note it on the drawing and mention any spec or inspection requirement when you send an RFQ. We will match it with shops set up to handle both the machining and the weld.

Frequently asked questions

Keep reading

• How to Turn Inconel 718: Insert Grades, Cutting Speeds and Chip Control
• Machining 3D Printed Inconel 718: Supports, HIP and Finish Stock