Material number G41300: 4130
G41300 is the Unified Numbering System designation for 4130, chromium-molybdenum low-alloy steel, weldable (chromoly) specified in ASTM A29.
What G41300 means
UNS numbers (ASTM E527 / SAE J1086) use a letter for the alloy family and five digits: G = AISI/SAE carbon and alloy steels (G41400 = 4140), S = stainless and heat-resisting steels (S30400 = 304), K = miscellaneous steels (K02600 = A36), T = tool steels, N = nickel alloys. The UNS number identifies a composition, not a product form or property level, so G41300 appears in several ASTM specifications (plate, bar, pipe) with different mechanical requirements.
4130 at a glance
AISI 4130 is the weldable chromoly: the same 1 % Cr / 0.2 % Mo alloying as 4140 but with carbon held to 0.28–0.33 %, so that a welded joint's heat-affected zone does not harden past the point of cracking. That single change made 4130 the aircraft-tube steel of the 1930s (MIL-T-6736) and it is still the material of race-car roll cages, aircraft fuselage frames and engine mounts, bicycle and motorcycle frames, go-kart chassis, sprint-car components and pressure-containing wellhead forgings. UNS G41300.
In the normalized condition — the usual state of 4130 tube — it offers about 435 MPa yield and 670 MPa tensile with 25 % elongation, roughly double mild steel at the same wall thickness, and it keeps good toughness. Quenched and tempered it reaches 860–1000 MPa (aerospace 125–145 ksi level) and, with care, 1240 MPa; deeper hardenability than plain carbon but less than 4140, so through-hardened sections are limited to about 25–35 mm.
EN 25CrMo4 (1.7218) is the usual European substitute (slightly lower carbon); JIS SCM430, GB 30CrMo and GOST 30KhMA are identical. Choose 4130 for welded, impact-loaded structures; 4140 for machined, heat-treated parts needing more strength.
Full data sheet for 4130 → · Equivalent grades →