D802 Cobalt base electrode

Quality D802 Cobalt Base Electrode ECoCr-A: Hard Core Guardian of High Temperature and High Pressure Valves”

In the field of hardfacing under extreme working conditions, when the parts need to withstand the triple test of high temperature, wear and corrosion at the same time, ordinary wear-resistant electrodes often appear inadequate. Quality DE D802 cobalt-based electrode (ECoCr-A)(modelEDCoCr-A-03), as a classic casting cobalt-chromium tungsten alloy electrode, with its excellent high temperature resistance, good scratch resistance and corrosion resistance, has become the preferred material for high temperature and high pressure valve sealing surface surfacing in electric power, chemical and metallurgical industries.
This electrode complies with stringent standards such asGB/T 984 andAWS A5.13and is designed for conditions where hardness and toughness are required at 650 ° C.

🔬Product core: Why choose quality D802?

The core competitiveness of QDE D802 cobalt-based electrode lies in its unique cobalt-chromium-tungsten alloy system:
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Excellent high temperature red hardness: This is the killer of this electrode. D802 hardfacing metal can keep good hardness (HRC40) and wear resistance at high temperature of650℃. It does not undergo allotropic transformation, which means that even in the hot state, its hardness does not drop as much as ordinary steel, and the hardness can be restored after cooling.
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Excellent scratch and corrosion resistance: High chromium and tungsten content gives weld metal excellent resistance to intermetallic wear (scratch resistance), especially suitable for high-load sliding contact surfaces. At the same time, its high alloy content makes it show strong chemical stability in the face of acidic media, steam and oxidation environment.
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Good comprehensive mechanical properties: Compared with high carbon D822 and other models, D802 belongs to low carbon and low tungsten type, so it has bettertoughness. It can effectively resist a certain degree of impact, avoid cracking under cold and hot alternating conditions, and achieve a perfect balance between hardness and toughness.
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Strong process adaptability: high quality D802 adopts advanced coating formula,AC and DC dual-use(recommended DC reverse connection), stable arc, easy slag removal, beautiful surfacing molding, minimal spatter.

📊Technical parameters and chemical composition

In order to facilitate you to quickly understand the inherent quality of this product, we have compiled the following core parameter table:

performance index	Typical values/ranges	remark
GB designation	EDCoCr-A-03 (D802)	Comply with GB/T 984
American Standard Model	ECoCr-A	AWS A5.13 compliant
main component	Co balance, Cr 25-32%	C 0.7- 1.4%, W 3-6%
hardfacing hardness	HRC ≥ 40	ambient hardness
operating temperature	≤ 650℃	long-term working temperature
main use	Valve sealing surface, hot shear blade	Shock and hot and cold intersection

🏭typical application scenarios

D802 Co-based electrode ECoCr-A“” is active in the following core industrial fields by virtue of its dual characteristics of heat resistance and corrosion resistance:
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Power & Plant Valves:
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Special forhigh temperature and high pressure valves (such as the main steam pipeline valve) sealing surface surfacing, is to prevent valve leakage of the key materials.
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Metallurgical and chemical machinery:
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Used for surfacing repair ofhot shear blade,high pressure pump sleeve,inner liner andchemical fiber equipment cutterto resist wear at high temperature.
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Hot mold:
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Apply tohot forging die,hot extrusion die surface strengthening, improve the service life of the die.
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Wear-resistant parts repair:
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Used for repairing parts bearing impact and cold and hot alternation under high temperature conditions, such as boiler rotating impeller, etc.

💡Welding process recommendations

In order to ensure the best performance of the quality D802 electrode, it is recommended that you follow the following process points during construction:
1.& nbsp;
Drying before welding: Before using the electrode, it must be baked at150-200℃for1 hour to remove moisture from the coating and prevent porosity.
2.& nbsp;
Preheating (critical):
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Because cobalt-based alloys are sensitive to cracks, preheating at300-600 ° C isnecessary depending on the size of the workpiece and the type of base metal.
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It is recommended to useDC reverse connection (electrode connected to positive electrode), low current and short arc welding to avoid excessive penetration of base metal and reduce the performance of surfacing layer.
3.& nbsp;
Control the interlayer temperature: During welding, it is recommended to control the interlayer temperature above250 ° Cto slow down the cooling rate.
4.& nbsp;
Post weld heat treatment:
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Tempering treatment at600-700℃ shall be carried out immediately after welding, and the temperature shall be kept for 1 hour and then slowly cooled with furnace.
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Or immediately put the workpiece into a dry hot sand box or straw ash to cool down to eliminate stress and prevent cracks.
5.& nbsp;
Transition layer design: in carbon steel or low alloy steel base metal large area surfacing, it is recommended to use Ni-Cr austenitic stainless steel electrode (such as A302/A307) surfacing a layer of transition layer.

📝sum up

High quality D802 cobalt-based electrode ECoCr-Ais the golden key to solve high temperature and high pressure valve sealing, hot die wear and corrosion resistant parts repair problems. It provides you with solid industrial protection with stable metallurgical quality and excellent high temperature performance.
If you are looking for a hardfacing solution that isresistant to high temperatures of 650 ° C,scratch resistance andgood toughness, the quality D802 ECoCr-A is undoubtedly your trusted industrial partner.