ASTM A572 is a high-strength low-alloy (HSLA) structural steel used across buildings, bridges, and heavy equipment wherever a design needs more strength per pound than plain carbon structural steel provides. The specification spans five grades — 42, 50, 55, 60, and 65 — built on a shared carbon-manganese base that's strengthened through small vanadium and/or niobium (columbium) additions rather than higher carbon content. That microalloying refines grain size and raises yield strength while keeping toughness and weldability in a workable range.

This page covers Grade 60, the second-highest strength level in the family, requiring a minimum yield strength of 60 ksi (414 MPa) and a minimum tensile strength of 75 ksi (520 MPa). It's a step down in strength from Grade 65 but still well above the general-purpose Grade 50 that dominates everyday structural work — Grade 60 shows up where designers need extra load capacity in heavy equipment frames, crane components, and structural members carrying above-average loads, without going all the way to the top of the A572 range.

As with the other higher A572 grades, Grade 60's added strength comes with tighter welding requirements than lower grades — preheat and heat-input control matter more to avoid cracking in the heat-affected zone. In the shop, that same strength and fine grain structure mean higher cutting forces and more aggressive tool wear than plain carbon structural steel of similar section size.

Grade 60's machinability sits between the general-purpose A572 grades and the top-of-the-line Grade 65. The microalloy grain refinement that delivers its strength also increases cutting forces and heat generation compared with plain carbon structural steel — the material resists shear deformation more, so a larger share of the cutting energy converts to heat right at the tool-chip interface.

Chip formation is generally more predictable than on soft mild steel: the higher strength promotes cleaner shear and better chip breaking once the insert has a chipbreaker matched to the operation, rather than the long stringy chips typical of low-carbon sheet steel. The tradeoff is faster flank wear, since the same fine grain structure and hardness that improve chip control also abrade the cutting edge more quickly.

Coated carbide grades with good hot hardness hold up noticeably better than uncoated tooling on this material for anything beyond light finishing work. Rigid workholding, sufficient coolant to manage the added heat load, and cutting speeds set below what would be used on plain carbon structural steel all help control tool wear and maintain part accuracy.