The Harris 4130 Chrome-Moly TIG (GTAW) Welding Rod, 1/16 in × 36 in, 10 lb Package (0413030) is a chromium-molybdenum steel filler specifically formulated to match the chemistry and mechanical properties of AISI 4130 base metal. Harris 4130 is the industry-standard TIG filler for motorsport roll cage fabrication, aircraft fuselage tubing, and structural chrome-moly tube assemblies where as-welded strength, predictable heat treatment response, and metallurgical compatibility with the base alloy are essential. The 1/16 in (1.6 mm) diameter is the correct size for thin-wall 4130 tube (0.049–0.095 in wall) at 40–110 A, threading cleanly around tight tube joints in 5G and 6G positions.
| Specification | Value |
|---|---|
| Manufacturer | Harris Products Group |
| Part Number | 0413030 |
| AWS Classification | ER80S-D2 (nearest AWS class) / Harris 4130 proprietary |
| Nominal Base Alloy Match | AISI 4130 (1.0% Cr, 0.2% Mo, 0.3% C max) |
| Diameter | 1/16 in (1.6 mm) |
| Length | 36 in (914 mm) |
| Package Weight | 10 lb (4.5 kg) |
| Tensile Strength (as-welded) | ~85,000 psi (586 MPa) typical |
| Tensile Strength (normalized) | ~95,000 psi (655 MPa) typical |
| Process | GTAW (TIG) |
| Polarity | DCEN (DC electrode negative) |
| Shielding Gas | 100% Argon |
| Preheat | 200–300°F (93–149°C) for wall > 0.120 in or high-restraint joints |
| Post-weld treatment | Normalize at 1,600°F (871°C) or stress relieve at 1,100°F (593°C) for maximum properties |
| Compatible Base Metals | AISI 4130, 4140, 4340, SAE 1025, DOM tubing |
| Motorsport Standards | SFI Foundation 25.5 / Appendix J cage material specifications accept 4130 filler |
Source: Harris Products Group 4130 chromoly technical data. AWS A5.28 ER80S-D2 is the closest standard classification for 4130-matching filler chemistry.
- Motorsport Roll Cage & Chassis Fabrication: SFI-specification roll cages in NASCAR, IMSA, rally, and sprint car classes mandate 4130 chromoly tubing; using 4130-matching filler ensures the weld deposit does not become the weak link. The 1/16 in diameter allows precise root fusion on 1.5 in OD × 0.095 in wall tube down to 1.0 in OD × 0.049 in wall used in kart and formula car construction.
- Aircraft Fuselage & Firewall: FAA AC 43.13-1B accepted method for welding 4130 steel aircraft structure includes matching 4130 filler or ER80S-D2. Airframe inspectors and DAR representatives accept Harris 4130 filler for repair and manufacture of steel tube fuselage assemblies per FAA standards.
- Bicycle Framebuilding: Reynolds 525, 631, and 853 chromoly frames — and custom lugged or TIG-welded frames — use 4130 or matching filler for joints that will be finished and painted without heat treatment, relying on the as-welded ductility of the filler to handle flex loading.
- Agricultural & Industrial Equipment: High-strength lift arms, loader frames, and pivot assemblies in 4130 or 4140 that require notch toughness and fatigue resistance beyond what ER70S filler provides.
- Military & Defense Ground Vehicles: Combat vehicle suspension components, armored hull brackets, and structural chrome-moly assemblies where metallurgical match to 4130/4140 is required by mil-spec.
As-welded vs. normalized strength: In the as-welded condition, a 4130 TIG joint retains good ductility and approximately 85 ksi tensile strength. Normalizing the entire weldment at 1,600°F (871°C) followed by air cooling raises tensile strength to ~95 ksi and improves toughness by refining the grain structure in the heat-affected zone. Stress relieving at 1,100°F (593°C) without normalizing reduces residual stress without dramatically changing the mechanical properties — preferred for tightly fabricated assemblies where distortion control matters.
4130 vs. ER80S-B2 for chrome-moly applications: ER80S-B2 contains 1.25% Cr and 0.5% Mo — designed specifically for P11 pressure pipe. Harris 4130 contains ~1.0% Cr and ~0.2% Mo to match AISI 4130 base metal. They are not interchangeable: use ER80S-B2 (see Lincoln ER80S-B2) for high-temperature pressure piping; use Harris 4130 for structural and motorsport chrome-moly applications. Substituting pressure pipe filler for 4130 structural applications can result in brittle welds without PWHT.
Preheat guidance for motorsport: For thin-wall 4130 tube under 0.120 in wall thickness, preheat is often omitted in motorsport and bicycle fabrication because the low heat input of TIG and thin section minimize the risk of hydrogen-induced cracking. For heavier wall (0.120 in+) or highly restrained joints (gussets welded to main cage hoops), preheat to 200–300°F. Always allow the weld to cool slowly in still air — do not quench with compressed air or water.
Browse all chrome-moly TIG rods in the TIG rod collection. For the DC TIG machine to run this filler, see the Lincoln Precision TIG 225.
Can I TIG weld 4130 chrome-moly without preheat?
For thin-wall 4130 tubing (under 0.120 in wall), TIG welding without preheat is accepted practice in motorsport and aerospace fabrication, provided the parts are at room temperature (above 50°F / 10°C) and the weld is allowed to cool slowly. The low heat input of TIG welding and the inherent low hydrogen of the process reduce cracking risk compared to SMAW. For heavy-wall sections or highly restrained joints, preheat to 200–300°F per AWS D10.8 or SAE AMS-W-6858 requirements.
What is the AWS classification for Harris 4130 filler rod?
Harris 4130 is a proprietary product formulated to match AISI 4130 base metal chemistry. The closest AWS A5.28 classification is ER80S-D2, which has a similar chromium-molybdenum content. Some Harris product documentation lists it as conforming to military specification MIL-E-18193 for 4130 filler. When code qualification is required (aerospace, pressure piping), verify that the specific Harris 4130 lot you are using has a certified mill test report showing chemistry and mechanical properties per the applicable qualification standard.
Is Harris 4130 filler acceptable for FAA-approved aircraft repairs?
Yes. FAA Advisory Circular AC 43.13-1B, Chapter 4 ("Welding") accepts TIG welding on 4130 steel aircraft structure using 4130-matching filler or ER80S-D2. The welder must be appropriately qualified, and the repair must be performed per an approved data source (STC, DER approval, or factory maintenance manual authorization). Harris 4130 filler is widely used in light aircraft maintenance and restoration.
What diameter 4130 rod do I need for 1.5 in OD x 0.095 in wall tube?
For 4130 tube at 0.095 in wall thickness, the 1/16 in (1.6 mm) diameter rod on this page is correct. You'll typically run 60–90 A DCEN with 100% argon shielding. The 3/32 in diameter (see Harris 4130 3/32 in) is better suited for heavier-wall tube (0.120 in and above) where more filler deposition per dip is needed to maintain travel speed and avoid excessive torch angle adjustments.