ER309LMo Welding Wire

By strictly controlling the welding environment conditions and shielding gas parameters, the welding quality of ER309LMo welding wire can be effectively improved, the corrosion resistance and mechanical properties of the weld can be guaranteed, and the needs of various industrial applications can be met.

1. Environmental conditions

• Temperature and humidity: It is recommended that the indoor temperature be kept above 5°C and the relative humidity not exceed 60%. Too low temperature may cause the weld to cool too quickly and increase the risk of cracks; too high humidity will affect the stability of the welding arc, increase the hydrogen content in the weld, and thus reduce the toughness of the weld.
• Storage conditions: The welding wire should be stored in a dry and well-ventilated environment, about 30cm from the ground and walls, to avoid moisture and contamination. This helps to keep the surface of the welding wire clean and prevent welding defects caused by moisture or impurities.

2. Shielding gas selection and flow

• Shielding gas composition: It is recommended to use 100% argon (Ar) or argon with 1%~3% oxygen (Ar+1%~3%O₂) as a shielding gas. Argon can provide good arc stability and reduce oxidation, while the addition of a small amount of oxygen can further improve the fluidity of the molten pool and make the weld more beautiful.
• Gas flow rate: The flow rate of shielding gas should be controlled at 20-25 liters/minute. The appropriate flow rate can effectively isolate the air, prevent nitrogen and oxygen from contaminating the molten pool, and avoid excessive airflow causing arc blow-off or eddy currents, which will affect the welding quality.

1. Preparation

• Cleaning welding materials

Before welding, you must ensure that the surface of the welding material is clean and free of grease, rust, oxides or other impurities. You can use acetone or alcohol to clean the welding area, and polish it with sandpaper or wire brush to remove the surface oxide layer.

• Choose suitable welding equipment

Use TIG welding machine to ensure that the equipment can provide stable DC reverse (DC-) power supply.
Prepare suitable tungsten electrode, usually pure tungsten electrode or thoriated tungsten electrode is recommended.

• Shielding gas preparation

Use 100% argon as shielding gas, and the gas flow rate is controlled at 15-25 L/min. The specific flow rate can be adjusted according to the welding current and environmental conditions.

• Welding parameter setting

Adjust the welding current and welding speed according to the wire diameter and welding position. For example:
Φ1.6mm welding wire, welding current is 130-160A, and welding speed is 80-150 mm/min.
Φ2.0mm welding wire, welding current is 140-180A, welding speed is 80-150 mm/min.

• Environmental requirements

The indoor temperature should be kept above 5°C, and the relative humidity should not exceed 60%.
The welding area should be kept dry, avoid wind speed exceeding 1.0 m/s, and take wind protection measures if necessary.

2. Welding operation steps

• Welding posture and angle

Hold the TIG welding gun firmly, maintain a suitable angle (usually 15-20 degrees) and distance (1-3mm).
Keep short arc operation during welding, and control the arc length to 1-3mm.

• Filling wire

The welding wire should be fed into the molten pool from the side of the arc to avoid direct contact with the tungsten electrode to avoid contaminating the electrode.
The feeding of the welding wire should be smooth and continuous to avoid excessive spatter.

• Welding process control

Maintain a stable welding speed during welding, avoid too fast or too slow.
Pay attention to the interlayer temperature control, it is recommended not to exceed 150℃.

• End of welding

At the end of welding, gradually reduce the current to avoid the formation of crater cracks at the end of the weld.

1. Preparation before welding

• Clean the welding area

Before welding, impurities such as rust, oil, moisture and dust must be thoroughly removed from the welding area to avoid welding defects.

• Choose a suitable shielding gas

Pure argon (Ar) or argon with 1%-3% oxygen (Ar + 1%-3% O₂) added as shielding gas is recommended. The gas flow rate is controlled at 20-25 L/min.

• Equipment settings

Use DC reverse connection (DC-), that is, the welding wire is connected to the positive electrode.
Adjust the welding current and wire feeding speed according to the wire diameter. For example, for a Φ1.2mm welding wire, the welding current is 160-200A.
The wire dry extension length is controlled at 15-25mm.

2. Welding operation steps

• Arc ignition

Use the welding machine to start the arc, and start welding after ensuring that the arc is stable.

• Welding process control

Maintain short arc operation, and the arc length is controlled at 1-3mm.
The welding speed should be moderate, avoiding too fast or too slow. Too fast may result in lack of fusion, too slow may cause overheating.
Keep the angle between the welding gun and the workpiece at 15-20 degrees.

• Multi-layer welding

If multi-layer welding is required, pay attention to control the temperature between layers not to exceed 150℃.

Although ER309LMo is mainly used for TIG or MIG welding, it can also be used for SAW welding under certain conditions.

1. Preparation before welding

• Clean the weldment: The welding surface must be thoroughly cleaned of impurities such as rust, oil, and moisture to prevent pores or cracks during welding.
• Choose the appropriate flux: Since ER309LMo welding is mainly used for TIG or MIG welding, if it is used for SAW welding, a matching stainless steel special flux must be selected.
• Equipment inspection: Ensure that the welding equipment, wire feeding system, and flux delivery system are in good condition.

2. Welding parameter setting

• Welding current: Select a suitable current range according to the wire diameter. For example, for Φ1.6mm welding wire, the welding current can be set at 130-160A.
• Welding voltage: Usually set at 20-25V, and the specific parameters need to be adjusted according to the wire diameter and welding position.
• Welding speed: It is recommended to control it at 80-150mm/min to ensure weld quality and penetration.
• Flux flow: Ensure that the flux covers the arc to prevent air pollution.

3. Welding operation

• Arc ignition: Align the wire to the starting point of welding and ignite the arc. Maintain a stable arc length, usually 1-3mm.
• Welding process:

→Maintain the angle between the welding gun and the weldment (about 15°-30°) to ensure that the welding pool is clearly visible.
→Move the welding gun evenly to avoid overheating or unfused welds.
→Ensure that the flux evenly covers the molten pool to prevent air pollution.

• Arc closure: At the end of welding, gradually reduce the current or use the arc crater filling function to avoid arc crater defects.

4. Precautions

• Interlayer temperature control: The interlayer temperature should be controlled below 150℃.
• Protective measures: During welding, ensure that the flux covers the molten pool to prevent oxygen and nitrogen in the air from contaminating the molten pool.
• Welding position: ER309LMo welding wire is suitable for all-position welding.
• Flux selection: If used for SAW welding, a stainless steel special flux matching ER309LMo must be selected.

ER309LMo Welding Wire packing

Mo-Containing Stainless Steel Welding Wire