Low Alloy & High Strength
ER120S-G
ER120S-G welding wire is an AWS A5.28 high-strength low-alloy solid welding wire classification for applications requiring ER120-strength weld metal and manufacturer-defined alloy chemistry. The G classification does not define one single fixed alloy chemistry, so the actual chemical composition, mechanical properties, toughness and application should be verified from the manufacturer's technical documentation and qualified welding procedure.
ER120S-G Welding Wire
ER120S-G is an AWS A5.28 high-strength low-alloy solid welding wire classification for applications requiring ER120-level weld-metal strength.
If you are sourcing ER120S-G welding wire, the most important question is not simply whether the wire meets the ER120 strength level. The actual consumable chemistry, base material, toughness, welding procedure and applicable code must also match the project requirements.
Is ER120S-G Suitable for Your Application?
ER120S-G may be considered for selected high-strength and low-alloy steel applications, including:
- High-strength steel fabrication
- Heavy machinery
- Industrial equipment
- Structural components
- Selected pressure-equipment applications
- High-strength fabricated components
Before selecting the wire, confirm:
Base Material → Required Strength → Toughness → Consumable Chemistry → Welding Process → WPS/PQR
Important: ER120S-G is a G classification. The classification does not identify one single standardized alloy chemistry. The actual product chemistry and performance should be verified from the manufacturer's technical documentation.
ER120S-G Key Specifications
Item | Details |
|---|---|
AWS Classification | ER120S-G |
AWS Specification | AWS A5.28 / ASME SFA-5.28 |
Product Type | Solid welding wire / TIG filler rod, depending on product |
Strength Classification | ER120 |
Alloy System | Manufacturer-defined low-alloy chemistry |
Welding Process | GMAW/MIG, GTAW/TIG, depending on product |
Typical Application | High-strength and low-alloy steel |
Main Selection Factors | Chemistry, strength, toughness and WPS/PQR |
Product Form | Spool / Rod |
Technical Documents | TDS / MTC / CoA according to requirements |
What Makes ER120S-G Different?
The “120” in ER120S-G identifies the ER120 strength classification, while the “G” designation means that the complete alloy chemistry is not represented by one specific standardized composition.
This is important when comparing products from different suppliers.
Two ER120S-G wires may have different chemical compositions and may therefore differ in:
- Weld-metal strength
- Toughness
- Hardenability
- Ductility
- Base-metal compatibility
- Welding procedure requirements
For this reason, ER120S-G should not be purchased by classification alone for critical applications.
The actual chemistry and test results should be checked against the project specification.
ER120S-G Chemical Composition
ER120S-G does not represent one universal chemical composition.
Depending on the manufacturer's product, controlled alloying elements may include:
- Carbon
- Manganese
- Silicon
- Chromium
- Nickel
- Molybdenum
- Copper
For project approval, request the actual chemical composition from the supplier.
Useful documents may include:
TDS · MTC · CoA · Chemical Analysis · Mechanical Test Data · Impact Test Results
The AWS A5.28 classification system covers chemical composition and weld-metal mechanical-property requirements for applicable low-alloy electrodes and rods, so the actual product documentation remains important when evaluating a specific ER120S-G product.
ER120S-G Strength and Mechanical Properties
ER120S-G belongs to the ER120 strength classification, corresponding to approximately a 120 ksi tensile-strength level.
However, the actual mechanical properties of a specific product depend on factors such as:
- Product chemistry
- Welding process
- Shielding gas
- Heat input
- Welding parameters
- PWHT
- Test temperature
- Qualification procedure
For engineering approval, verify:
Tensile Strength + Yield Strength + Elongation + Impact Toughness
Do not assume fixed mechanical values from the ER120S-G designation alone.
Where Is ER120S-G Used?
ER120S-G can be considered for applications where high weld-metal strength is required and the consumable is compatible with the base material and welding procedure.
High-Strength Steel
For compatible high-strength and low-alloy steels requiring high-strength weld metal.
Heavy Machinery
For selected heavy-duty machinery and fabricated components where weld strength is an important design requirement.
Industrial Equipment
For industrial structures and equipment requiring high-strength weld-metal properties.
Pressure Equipment
For selected pressure-equipment applications where chemistry, toughness, mechanical properties, heat treatment and applicable codes have been qualified.
Actual application suitability depends on the specific ER120S-G product and project requirements.
Welding Processes for ER120S-G
Depending on product form and manufacturer's specification, ER120S-G may be supplied for:
GMAW / MIG
Important variables include:
- Wire diameter
- Shielding gas
- Current
- Voltage
- Wire-feed speed
- Travel speed
- Heat input
GTAW / TIG
Where supplied as a TIG filler rod, ER120S-G may be used for applications requiring controlled deposition, such as:
- Pipe root passes
- Precision welding
- Critical joints
- Controlled weld-metal deposition
Actual welding parameters should follow the qualified WPS.
Welding Procedure Considerations
High-strength welding consumables require controlled welding procedures.
Important variables may include:
Preheat · Interpass Temperature · Heat Input · Cooling · PWHT
The required procedure depends on:
- Base-metal grade
- Material thickness
- Joint design
- Welding process
- Hydrogen-control requirements
- Service conditions
- Applicable code
- WPS/PQR
Avoid using generic preheat or PWHT values as a substitute for the qualified welding procedure.
ER120S-G Selection: What Should Buyers Check?
Before ordering ER120S-G, confirm the following:
Base Material
Identify the exact steel grade and applicable material specification.
Weld-Metal Strength
Confirm the required tensile strength and yield strength.
Toughness
Check whether Charpy impact testing is required and identify the test temperature.
Consumable Chemistry
Confirm whether the project specifies particular alloying elements.
Welding Process
Specify GMAW/MIG or GTAW/TIG.
Heat Input
Check whether the WPS or project specification limits heat input.
Preheat and Interpass
Follow the temperature range specified by the qualified welding procedure.
PWHT
Confirm whether post-weld heat treatment is required.
Certification
Determine whether MTC, CoA, impact data or third-party inspection is required.
ER120S-G vs Other High-Strength Welding Wires
ER120S-G belongs to the same broader high-strength wire family as ER100S-G and ER110S-G, but the strength classification is not the only selection factor.
Welding Wire | Strength Classification | Chemistry | Main Selection Focus |
|---|---|---|---|
ER90S-G | ER90 | Manufacturer-defined | High-strength applications |
ER100S-G | ER100 | Manufacturer-defined | Higher-strength applications |
ER110S-G | ER110 | Manufacturer-defined | Very high-strength applications |
ER120S-G | ER120 | Manufacturer-defined | Very high-strength requirements |
ER120S-G vs ER110S-G
ER120S-G has a higher strength classification than ER110S-G.
However, this does not automatically make ER120S-G a replacement.
Compare:
Strength + Toughness + Chemistry + Base Material + WPS/PQR
ER120S-G vs ER100S-G
ER120S-G represents a higher strength classification than ER100S-G.
The higher strength level must still be compatible with the base material, toughness requirements and qualified welding procedure.
ER120S-G vs ER90S-G
Both are G-classification solid wires, but their strength levels are different.
ER120S-G is approximately a 120 ksi strength classification, while ER90S-G is approximately a 90 ksi strength classification.
Actual chemistry and mechanical properties remain product-specific.
ER120S-G vs Cr-Mo Welding Wires
ER120S-G should not be selected simply because its strength classification is higher than a Cr-Mo consumable.
For example:
ER120S-G vs ER90S-B9/B91
Factor | ER120S-G | ER90S-B9/B91 |
|---|---|---|
Classification | G | B9/B91 |
Strength Level | ER120 | ER90 |
Chemistry | Manufacturer-defined | Specific Cr-Mo system |
Typical Focus | High-strength applications | P91/T91-related applications |
Key Selection | Chemistry + strength + toughness | Cr-Mo chemistry + heat treatment + WPS/PQR |
ER120S-G vs ER90S-B3
ER120S-G and ER90S-B3 are designed around different selection requirements.
ER90S-B3 is associated with specific Cr-Mo applications such as P22/T22, while ER120S-G is a manufacturer-defined G-classification high-strength wire.
A higher strength classification does not make ER120S-G a substitute for a Cr-Mo consumable.
Can ER120S-G Replace Another Welding Wire?
Not automatically.
Before substitution, evaluate:
- Base material
- Tensile strength
- Yield strength
- Impact toughness
- Elongation
- Actual consumable chemistry
- Hydrogen-control requirements
- Preheat and interpass requirements
- PWHT
- Applicable code
- Customer specification
- WPS/PQR
A higher-strength welding wire is not automatically an approved replacement.
Diameter and Packaging
ER120S-G may be available in different diameters and packaging formats depending on the specific product.
Possible formats include:
- MIG/GMAW spools
- TIG/GTAW rods
- Different wire diameters
- Standard packaging
- Customized packaging
For quotation, provide:
AWS Classification + Diameter + Base Material + Welding Process + Application + Quantity
Technical Documentation
For ER120S-G projects, buyers may request:
- Technical Data Sheet (TDS)
- Mill Test Certificate (MTC)
- Certificate of Analysis (CoA)
- Chemical composition
- Mechanical properties
- Impact test data
- Certificate of Conformity
- Packaging information
- Project-specific documentation
Because the G classification does not identify one fixed alloy chemistry, these documents are particularly important when approving ER120S-G for demanding applications.
Frequently Asked Questions
What is ER120S-G welding wire?
ER120S-G is an AWS A5.28 high-strength low-alloy solid welding wire classification with an ER120 strength level and manufacturer-defined alloy chemistry.
What does G mean in ER120S-G?
The G designation identifies a classification where the complete chemical composition is not represented by one specific standardized alloy system.
Is ER120S-G a high-strength welding wire?
Yes. ER120S-G belongs to the ER120 strength classification, corresponding to approximately a 120 ksi tensile-strength level.
What is ER120S-G used for?
Its application depends on the actual product chemistry, base material and qualified welding procedure. It may be used for selected high-strength low-alloy, structural, industrial and pressure-equipment applications.
What is the difference between ER110S-G and ER120S-G?
ER120S-G has a higher strength classification than ER110S-G. However, chemistry, toughness and welding qualification must also be considered.
Can ER120S-G replace ER110S-G?
Not automatically. The base material, mechanical properties, toughness, chemistry and WPS/PQR must support the substitution.
Can ER120S-G replace ER100S-G?
Not automatically. Strength classification alone does not establish consumable equivalency.
Can ER120S-G be used for P91 steel?
Do not assume it is suitable. P91 applications require consumables compatible with the specific Cr-Mo alloy system, heat-treatment requirements and qualified welding procedure.
Can ER120S-G replace ER90S-B9 or ER90S-B91?
Not automatically. ER120S-G is a G-classification high-strength wire, while B9/B91 represents a specific Cr-Mo alloy system.
What welding processes can use ER120S-G?
Depending on the product form and manufacturer's specification, ER120S-G may be supplied for GMAW/MIG and GTAW/TIG.
Does ER120S-G require PWHT?
PWHT depends on the base material, thickness, welding procedure and applicable code. Follow the qualified WPS/PQR.
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