We know you have questions about WALDUN, and we love answering them!
Here are some of the questions we are asked most frequently:
What is hardfacing?
Overlap welding can increase the size of the welded workpiece. It is a kind of surface engineering to recover the welded parts or the deposited metal, which has unique properties. Hardfacing using a welding heat source, form a molten metallurgical bond between the surface of the base material and the material deposited on a surface engineering surface. Its purpose is to borrow welding, in the parts of the deposition of one or more layers of material, to obtain the required wear-resistant, heat-resistant, corrosion-resistant, and other special properties deposited layer.
What are the types of overlays?
There are four main types of overlays.
- Abrasion-resistant hardfacing: to reduce the abrasive abrasion, corrosion, impact, or cavitation of the welded surface of the hardfacing layer used.
- cladding hardfacing: to make the surface corrosion resistance, in carbon steel or alloy steel base material on the hardfacing of a certain thickness of filler metal.
- Isolation layer hardfacing: Welding of dissimilar materials, or special requirements, to ensure the quality and performance of the joint, to do isolation of the base material in advance.
- Thickening hardfacing: on the surface of the weld, joint edges, or to restore the required size of the component to add metal.
How to avoid cracking in hardfacing?
Here’s what we need to know.
1.Preheat before welding, control the temperature between layers, slow cooling after welding.
2.After welding for stress relief heat treatment.
3.Avoid multi-layer hardfacing cracking using a low-hydrogen type hardfacing electrode.
4.If necessary, hardfacing layer and the base material between the transition layer hardfacing (with low carbon equivalent, high toughness electrodes)
What are the common defects in hardfacing layers?
1.Defects in the hardfacing metal such as porosity, inclusions.
2.Unfused (not combined) between the hardfacing layer and the base metal (substrate), the orientation is parallel to the base metal’s surface.
3.The reheating crack in the base metal’s heat-affected zone under the hardfacing layer, the direction is perpendicular to the surface of the base metal.
What are the commonly used inspection methods for hardfacing layers?
1.For defects within the cladding layer. Generally, using a longitudinal wave direct crystalline probe from the cladding layer side or the detection’s base metal side.
2.For the cladding layer and the base material of the unbound defects between, Generally, used longitudinal wave straight probe, from the base metal side of the detection or longitudinal wave bimetallic probe from the cladding layer side of the detection.
3.Generally, using longitudinal wave bimetallic straight probe or slanted head from the cladding layer side of the detection.
What is the connection between welding and cladding?
Welding and welding overlay are two different technologies, and there is no relationship between them.
Welding: Welding is a manufacturing process and technique of joining metals or other thermoplastic materials such as plastics using heat, high temperature, or high pressure.
hardfacing: hardfacing, as an economical and rapid process method for surface modification of materials, is becoming more and more widely used in the manufacturing and repairing parts in various industrial sectors. It can make the most effective use of the hardfacing layer. It is desirable to use hardfacing methods with less dilution of the base material, higher deposition rates, and excellent hardfacing layer properties. i.e., high quality, efficient and low dilution rate hardfacing techniques.
What are the main types of hardfacing alloys?
Hardfacing alloys mainly include. Iron-based wear alloy, nickel-based wear alloy, cobalt-based wear alloy, tungsten carbide wear alloy, ceramic composite, etc.
What are the methods of hardfacing?
Flame hardfacing; manual arc hardfacing; submerged arc hardfacing; melt electrode gas shielded hardfacing; tungsten argon arc hardfacing; plasma arc hardfacing; electro-slag hardfacing.
What is the hardness of the surface and cross-section of the hardfacing layer?
The hardness of the weld overlay surface depends on the hardness of the welding consumables used, generally from 15 to 65 HRC. The cross-sectional hardness distribution is more uniform, related to its metallurgical structure.
Why are there so many cracks on wear plates?
Due to the cooling rates of dissimilar metals. Our hardfacing wear plates for coal chute liner is manufactured by welding which results in high temperatures. During the cooling, the plate goes through a stress relieving which is a natural process and does not effect the performance of the plate. The stress relief cracks should be between 3/4″ – 2″ apart. The cracks can be touched up by our chrome carbide welding rod.
What is the best method of attachment for wear plates?
Hardfacing plate for coal chute liner is usually attached by countersunk bolts, welding studs, perimeter welding, or plug welding.Some methods are better suited than others depending on the specific application. For more detail on each method see the installation section.
Can hardfacing plate for coal chute liner be drilled or machined?
Hard facing plate for coal chute liner cannot be machined or drilled. It can however be ground. Mild steel inserts are used to create countersunk or counter bored holes. hard facing plate for coal chute liner can be cut using plasma, Grinding wheel saw, or air-arc gouging.
How about MOQ of your wear products?
Our product has no limit to quantity, it can be ordered according to customer requirement.
What’s the service life compare with Hardox series?
Generally speaking, our bimetallic overlay wear plate is 4.5~8 times than Hardox series in service life.
Are you able to produce customized chemical composition and dimension?
Yes, we could offer special welding wires and wear overlay plates according customers’ requirements.
How long is your delivery time?
Generally it is 5-10 days if the goods are in stock. or it is 15-25 days if the goods are not in stock, it is according to quantity.
Do you provide samples ? is it free or extra ?
Yes, we could offer the sample for free charge.
What is your terms of payment ?
We accept TT,LC.If you have good credit, we can accept OA.
Do you provide after-sales service?
Our company has a professional after-sales service team, with many years of experience not only on hardfacing products and applications, but also on the operation of application equipment. We are able to quickly solve customer’s problems. If there are any quality problems, the responsible person will provide reasonable solutions within 12 hours after being notified.