Chromium Carbide Hardfacing for Slurry Transport Pipes
Chromium Carbide Hardfacing for Slurry Transport Pipes
(OP)
I am researching this class of hardfacing alloy for 24~36" carbon steel pipes (and elbows) for transport of sand-bearing slurry in slightly acidic water. The primary wear mode is corrosive-abrasive wear. Clad thickness is 1/4~5/16 inch. The object is to improve service life.
Chromium carbide (CC) hardfacing (~30% Cr, 4-6% C) is the industry standard, but for the proposed environment suffers from lack of corrosion resistance. It is also vulnerable to weld cracking down to the CS substrate, leading to rapid corrosion and other more drastic wear modes (large chunks breaking off). What I've found so far is that ~30% blocky primary carbide phase (Cr7C3) is optimum for abrasion resistance; I know less about the matrix structure. The composition relative to the eutectic point appears to be a major factor influencing properties. Abrasion resistance and hardness properties (>50 HRC) are fairly easy to achieve; corrosion resistance and fracture toughness are more elusive.
I am seeking experiences from metallurgists/welding engineers, fabricators and end users. Welding processes/techniques, electrode vendors (I prefer subarc), composition, effects of additional alloying elements (B, Ti, Mo, Ni, ...), any and all pitfalls. Ideally the matrix would be austenitic stainless for toughness and corrosion resistance, but is it possible? Micrographs with descriptions are most welcome.
Chromium carbide (CC) hardfacing (~30% Cr, 4-6% C) is the industry standard, but for the proposed environment suffers from lack of corrosion resistance. It is also vulnerable to weld cracking down to the CS substrate, leading to rapid corrosion and other more drastic wear modes (large chunks breaking off). What I've found so far is that ~30% blocky primary carbide phase (Cr7C3) is optimum for abrasion resistance; I know less about the matrix structure. The composition relative to the eutectic point appears to be a major factor influencing properties. Abrasion resistance and hardness properties (>50 HRC) are fairly easy to achieve; corrosion resistance and fracture toughness are more elusive.
I am seeking experiences from metallurgists/welding engineers, fabricators and end users. Welding processes/techniques, electrode vendors (I prefer subarc), composition, effects of additional alloying elements (B, Ti, Mo, Ni, ...), any and all pitfalls. Ideally the matrix would be austenitic stainless for toughness and corrosion resistance, but is it possible? Micrographs with descriptions are most welcome.





RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
Not wishing to set you off on a tangent, have you investigated cast Basalt liners for that application?
http://www.abresist.com/ABRESIST_Linings.htm
B.E.
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
There are other materials out there. Some are more crack resistant than others. In my experience, you will sacrifice some abrasion resistance to achieve a crack-free applicaiton, so you will have a trade-off.
There are other hardfacting materials that you may want to investigate. The Titanium Carbide materials will give nearly the same abrasion resistance with less cracking. There are also Boron-based (as opposed to Carbon-based) materials that may hold promise.
rp
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
rmw
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
http://www.cbpengineering.com/pdf/CBP-Basalt_Pipe....
rmw
I have used beaucoup chrome carbide plate as fan and ductwork liners for gas sterams laden with abrasive materials - and it was just dandy. Those however, were dry processes where the myriad of surface cracks present offered no particular disadvantage. The substrate carried the stress load. People who were serious about slurry pipelines used Basalt. The planned to turn the pipe 120 degrees every 10 years in order to get a 30 year life out of the pipe. Others just replaced entire pipe runs more often.
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
http://www.iracore.com/lined-pipe-system.aspx
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
rmw
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
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Plymouth Tube
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
One of my project goals is overcoming the poor impact resistance and erosion-corrosion properties of CrC hardfacing. Do you know of formulations that give a tougher and more corrosion-resistant matrix? There are big trade-offs in this game, but I am prepared to give up some of the abrasion resistance and hardness that the CrC class has in abundance. Cost is not the foremost consideration at this point in time.
"If you don't have time to do the job right the first time, when are you going to find time to repair it?"
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
You may want to check out Hardface Technologies from Postle Industries; they are rather knowledgeable and have a wide range of products.
rp
RE: Chromium Carbide Hardfacing for Slurry Transport Pipes
I would go with rmw's recommendation of using ceramic tiles. These last long , are abrasion resistant and can withstand impact. The only consideration is cost.
In thermal power stations, where a lot of coal is transported ( in countries like India, more rocks and less coal) they are standing the test.A few years ago for a coke oven plant in a large steel plant , 3 materials were tried, manganese steels, high chrome iron and ceramic liners. Manganese liners wore out in 2 weeks, high chrome liners in about 12 weeks, but the ceramic liners lasted very long without breakage. However the cost of these ceramic liners was very high , my high chrome liners was selected as candidate material for the purpose.
Just last week, I had supplied for a bentonite grinding plant, plough blades hard faced with high chromium content and a hardness of 550BHN. They wore away in just 5 days. I am still battling for a solution.