Is ASTM A572 Grade 60 prequalified under AWS D1.1:2025?

Yes. A572 Grade 60 is listed among the prequalified base metals in AWS D1.1:2025. However, the higher carbon and manganese content permitted for Grade 60 to achieve its 60 ksi yield — compared to Grade 50 — means the carbon equivalent (CE) is likely to push preheat requirements up. A prequalified WPS still requires preheat per Table 6.3 based on the actual MTR heat chemistry.

What filler metal should I use for A572 Grade 60?

E7018 or E8018 (SMAW), ER70S-6 or ER80S-D2 (GMAW), or E71T-1/E81T1 (FCAW-G) are appropriate choices. E70XX fillers with minimum tensile of 70 ksi are acceptable since the A572 Grade 60 specified minimum tensile is 75 ksi — a modest overmatch that AWS D1.1 allows. For higher-CE heats or heavy sections in restraint, E8018 provides an additional margin.

How does the WPS for A572 Grade 60 differ from Grade 50?

The WPS structure is the same, but Grade 60 typically requires higher minimum preheat due to higher carbon equivalent values permitted by the A572 specification. Grade 50 often qualifies with 50–100°F preheat on moderate wall thicknesses; Grade 60 more commonly requires 150–200°F on sections above 3/4 inch, particularly when the MTR shows C > 0.22% or Mn approaching the top of its range.

Can I use an existing Grade 50 WPS for Grade 60 without requalification?

No. A572 Grade 60 is a higher strength level than Grade 50 and may be in a different base metal group in the AWS D1.1 essential variable tables. Even if both fall within the same prequalified group, a change in base metal specification that increases preheat requirement constitutes a change that must be reflected in the WPS — the preheat entry on the WPS must match the actual CE-based requirement for Grade 60.

Oct 18, 20267 min read

A572 Grade 60 Structural Steel WPS Under AWS D1.1:2025

WPS qualification guide for ASTM A572 Grade 60 structural steel under AWS D1.1:2025, covering prequalified status, preheat, filler metal selection, and how Grade 60 differs from Grade 50 in WPS practice.

WPS A572 Grade 60 AWS D1.1 Structural Steel PQR

ASTM A572 Grade 60 is the high end of the standard high-strength low-alloy (HSLA) structural plate and shape spec — sitting above the ubiquitous Grade 50 and below the Q&T world of A514. For structural engineers, Grade 60 offers meaningful weight savings on heavily loaded members without stepping into the more demanding welding procedures of true high-strength steels. For welding engineers and CWIs, it requires attention: the chemistry flexibility A572 allows for Grade 60 to hit its yield target creates real variation in carbon equivalent from heat to heat.

This article covers WPS qualification for A572 Grade 60 under AWS D1.1:2025 — prequalified status, preheat, filler selection, and the practical differences from the Grade 50 welding procedures already in most shops' libraries.

What A572 Grade 60 Specifies

ASTM A572 covers five grades of high-strength low-alloy columbium-vanadium structural steel. Grade 60 specifies:

Fy: 60 ksi minimum
Fu: 75 ksi minimum
Elongation: 16% in 8-inch gauge length (or 18% in 2-inch gauge length depending on product form)

The chemistry limits in A572 for Grade 60 are notably flexible compared to Grade 50. Carbon content up to 0.26% is permitted for plates and shapes, versus 0.23% for Grade 50. Manganese can run up to 1.35% for Grade 60. Vanadium and columbium microalloy additions are also common for Grade 60 to boost yield through grain refinement and precipitation hardening without raising carbon.

The practical result: Grade 60 from one mill heat may have CE = 0.47 while Grade 60 from another heat has CE = 0.60. A WPS written with 100°F preheat based on the first heat is non-compliant for the second heat. This is the central lesson of welding A572 Grade 60 — the MTR chemistry, not the grade designation, drives the WPS preheat.

Prequalified Base Metal Status

AWS D1.1:2025 includes A572 Grade 60 in the prequalified base metal listing under Clause 5. A shop can write a prequalified WPS for Grade 60 using:

SMAW with E70XX or E80XX low-hydrogen electrodes
SAW with approved wire-flux combinations
GMAW (spray or globular transfer) with ER70S or ER80S wire
FCAW-G with E70T or E80T-type electrodes

Short-circuit GMAW is not prequalified for groove welds. FCAW-S (self-shielded) is not prequalified for CJP groove welds. These restrictions apply to A572 Grade 60 the same as any other base metal under Clause 5.

Prequalified status means no PQR testing is required — but the WPS must still accurately reflect the CE-based preheat for the specific heat being welded. Writing "preheat: 50°F minimum" on a prequalified WPS for Grade 60 because Grade 50 gets away with it is a compliance failure when the MTR shows CE = 0.55.

Carbon Equivalent and Preheat

The CE formula under AWS D1.1:2025 is:

CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15

Work through two common A572 Grade 60 heat chemistries:

Lower CE heat: C = 0.22%, Mn = 1.10%, V = 0.04% (no Cr, Mo, Ni, Cu)
CE = 0.22 + (1.10/6) + (0.04/5) = 0.22 + 0.183 + 0.008 = 0.41 CE
→ AWS D1.1:2025 Table 6.3 preheat: ~50–100°F for sections up to 1.5 inches

Higher CE heat: C = 0.25%, Mn = 1.30%, V = 0.07%, Nb = 0.04%
CE = 0.25 + (1.30/6) + (0.07/5) = 0.25 + 0.217 + 0.014 = 0.48 CE
→ AWS D1.1:2025 Table 6.3 preheat: ~150°F for sections above 3/4 inch

The span between these two legitimate Grade 60 heats is significant — 50°F versus 150°F minimum preheat. A WPS written for the low-CE heat does not comply for the high-CE heat. This is why structural fabrication protocols for A572 Grade 60 should include a preheat calculation step tied to each heat of plate or shape used in production.

Filler Metal Selection

For A572 Grade 60 (Fu = 75 ksi minimum), the conventional approach is to use E70XX filler, which at 70 ksi minimum tensile provides a slight undermatching of the base metal's 75 ksi specified minimum. AWS D1.1 does not require tensile overmatching as an absolute rule — the connection design by the structural engineer accounts for weld metal strength.

That said, many WPS libraries for Grade 60 default to E80XX/ER80XX filler to:

Provide a clear overmatch margin across all Grade 60 heats
Avoid questions from inspectors or design reviewers about the undermatching scenario
Allow the same filler to be used for Grade 60 and A514 Grade B repair work in the same shop

SMAW: E8018-C3 (nickel-bearing) provides excellent toughness at low temperatures and good weldability. E8018-B2 (Cr-Mo alloying) is not appropriate for structural A572 — reserve it for pressure vessel applications. E7018 is acceptable for Grade 60 in non-critical applications.

GMAW: ER70S-6 is standard; ER80S-D2 (manganese-molybdenum alloying) provides higher strength for heavy structural applications.

FCAW-G: E71T-1 classified electrodes cover Grade 60 applications. E81T1-type electrodes match to E80 filler strength level when specified.

Low-hydrogen discipline is required for Grade 60. For SMAW, this means H8 or H4 suffix electrodes stored in a rod oven at 250–300°F after opening. Electrodes left on the bench overnight in a humid shop environment accumulate moisture that defeats the purpose of the low-hydrogen classification and creates the conditions for underbead cold cracking — exactly the failure mode that targeted Grade 60's higher CE makes possible.

WPS Parameters for Common Grade 60 Applications

Fillet Welds (Prequalified)

Minimum preheat per MTR CE calculation. Maximum single-pass fillet weld leg size depends on position — AWS D1.1:2025 Clause 5 limits maximum single-pass fillet weld sizes to control heat input and prevent excessive penetration. For Grade 60, single-pass fillet welds up to 5/16 inch are standard in the flat position.

Minimum preheat for Grade 60 fillet welds on sections above 3/4 inch when CE > 0.45%: 150°F minimum.

CJP Groove Welds (Prequalified, SMAW)

Root pass: E6010 is permitted for prequalified CJP groove weld root passes under AWS D1.1 Clause 5, even for Grade 60. However, given Grade 60's elevated CE in many heats, the use of E7018 root pass is a safer practice that reduces hydrogen risk in the root — the most restrained and highest-stress location in the joint.

Fill and cap passes: E7018 or E8018, low-hydrogen, from a sealed container or rod oven.

Heat input should be managed to stay within the prequalified range. For Grade 60 with CE > 0.50%, excessive heat input contributes to grain coarsening in the HAZ and can reduce notch toughness — a concern if the project specifies CVN testing.

CVN Requirements

If the project specification invokes supplementary CVN requirements (e.g., for fracture-critical applications or cold service), the WPS becomes a tested WPS under AWS D1.1:2025 Clause 6, and Table 6.8 supplementary essential variables apply. A change in preheat, heat input, electrode type, or base metal CE range that was not encompassed in the PQR test triggers requalification.

For non-supplementary CVN projects (the majority of structural fabrication under AWS D1.1), the prequalified WPS route with CE-based preheat is the standard approach for Grade 60.

Grade 60 vs. Grade 50: Practical Differences in the Shop

Parameter	Grade 50 typical	Grade 60 typical
CE range	0.38–0.48	0.42–0.60
Minimum preheat (3/4 in plate)	50–100°F	100–200°F
Filler metal	E7018 / ER70S-6	E7018 or E8018
Low-H discipline	Required	Mandatory
MTR review required	Yes	Yes — more critical

The structural engineer who specifies Grade 60 for weight savings often does not coordinate the welding procedure implications with the fab shop. Before accepting a Grade 60 job, review the structural drawings for weld sizes and joint configurations, calculate the CE range from representative MTR data, confirm your preheat capability (adequate heating equipment for 150–200°F soak on large sections), and update the WPS preheat entry to match.

A WPS software platform with integrated CE calculator and preheat lookup reduces the risk of a WPS that doesn't reflect the actual heat chemistry. See how WPS management works for structural fab shops.

CWI Inspection Notes for Grade 60

CWIs inspecting Grade 60 joints should:

Verify MTR CE at preheat sign-off. Don't accept a preheat temp-stik check if the WPS preheat is based on Grade 50 assumptions. Confirm the WPS preheat matches the MTR CE for the Grade 60 heat in production.
Check rod storage. E8018 electrodes should be in a portable rod oven or returned to the main oven after each shift. Exposure over 4 hours out of oven voids the low-hydrogen classification.
Interpass temperature maximum. Document interpass temps on the production record — for Grade 60 multi-pass welds on heavy sections, interpass temp above 400°F can degrade toughness properties in the HAZ.
Visual acceptance. AWS D1.1 visual acceptance criteria for crack, undercut, overlap, and profile apply the same as for Grade 50 — but Grade 60's higher CE makes weld cracks more likely if hydrogen or preheat controls fail. Any crack indication on Grade 60 is a serious non-conformance requiring full investigation before repair.

Rule library based on AWS D1.1:2025. Verify against your governing edition — the AHJ or contract may specify 2020 or an earlier edition.

Frequently asked.

Is ASTM A572 Grade 60 prequalified under AWS D1.1:2025?: Yes. A572 Grade 60 is listed among the prequalified base metals in AWS D1.1:2025. However, the higher carbon and manganese content permitted for Grade 60 to achieve its 60 ksi yield — compared to Grade 50 — means the carbon equivalent (CE) is likely to push preheat requirements up. A prequalified WPS still requires preheat per Table 6.3 based on the actual MTR heat chemistry.
What filler metal should I use for A572 Grade 60?: E7018 or E8018 (SMAW), ER70S-6 or ER80S-D2 (GMAW), or E71T-1/E81T1 (FCAW-G) are appropriate choices. E70XX fillers with minimum tensile of 70 ksi are acceptable since the A572 Grade 60 specified minimum tensile is 75 ksi — a modest overmatch that AWS D1.1 allows. For higher-CE heats or heavy sections in restraint, E8018 provides an additional margin.
How does the WPS for A572 Grade 60 differ from Grade 50?: The WPS structure is the same, but Grade 60 typically requires higher minimum preheat due to higher carbon equivalent values permitted by the A572 specification. Grade 50 often qualifies with 50–100°F preheat on moderate wall thicknesses; Grade 60 more commonly requires 150–200°F on sections above 3/4 inch, particularly when the MTR shows C > 0.22% or Mn approaching the top of its range.
Can I use an existing Grade 50 WPS for Grade 60 without requalification?: No. A572 Grade 60 is a higher strength level than Grade 50 and may be in a different base metal group in the AWS D1.1 essential variable tables. Even if both fall within the same prequalified group, a change in base metal specification that increases preheat requirement constitutes a change that must be reflected in the WPS — the preheat entry on the WPS must match the actual CE-based requirement for Grade 60.