Applications> Application Recommendations Electric Arc (SMAW) << Applications Application Recommendations rods and cored electrodes for hardfacing - hardfacing
Applications> Application Recommendations Electric Arc (SMAW)
AgroTec / AgroTec - E
ARC - SMAW
- Remove rust, dirt, grease, oil and other contaminants from the surface to be protected prior hardfacing deposits should be removed using: brush, sandblasting machine, grinder, etc. If it is not possible to completely remove all traces of previous recharge, applying a layer of "buttered" or reconstruction and then reload.
Preheating the part to recharge is advisable in all cases under the following parameters:
Preheat to prevent landslides, fissures and cracks in the contribution base material or under lace, high hardness zones adjacent to the cord. Pores are also avoided by hydrogen.
Holding temperatures during recharge. Interpass temperature. In all cases the subsequent cooling of the part should be slow, which helps to reduce residual stresses. Isolate the piece in dry sand, vermiculite or dry lime. Cracks can appear not affect product performance.
- Manganese steels: Never exceed 260 ° C.
- Cast iron: Preheat to 450 ° C and maintained throughout the process.
- Low Alloy Steel: Preheat to 150/250 ° C.
Dilution: Excessive penetration and / or dilution reduces hardness, recharge performance and may cause cracks or embrittlement of the workpiece.
The following procedures reduce dilution:
The combination of low amperage and the procedure to "push" the sink with bow helps minimize dilution and helps produce deposits of high strength carbide.
- Do not use excessive current / amperage.
- Direct the arc to the pool of molten metal instead of the base metal.
Prevent an excessively thick deposit does not contribute to the wear resistance and can be started rapidly or cracking.
- Use overlapping strands (50 to 75%).
- Preheat at recommended temperatures.
Deformation: The heat produced in the process can produce deformations of the piece affecting later use. Use methods clamping and welding procedures to prevent deformation. Preheat slowly and evenly.
Amps 150/160 to 5 mm. 120/150 to 3.5 mm.
The amperage range is adjustable to "comfort" welder in speed, dilution, bead width, etc. Obviously not turn too low amperage (hits) and excessive overheating putting the red rod.
Use machines over 400 Amp regulated power to the powers listed above, this facilitates starting and continuity of the post.
Voltage; no specific requirements have experiences from 25 to 35 volts, to adjust welder convenience, features of the piece, the work piece weight, etc.
DC, Polo (+).
The best result is obtained if the base metal is SAE 1010.
When the dimensions lace permit, improves application if the cord feed is produced using a circular motion. Try to rotate in the direction of clockwise or counterclockwise, the performance will be better in one direction depending on the location of the clamp (-)
The electrode should be positioned at 75/90 ° to the base metal.
Preheat the rods for one hour at 100 ° C minimum.
Take the rod clamp to 15/20 cm from the tip to prevent overheating of the rod.
With two passes obtain maximum hardness.
Fumes from the normal use of these products may contain traces of chromium, manganese or tungsten therefore be applied in ventilated areas.