Mud pump is the most important part in oil drilling system, and the mud pump liner is the main wear part of mud pump fluid end, so the service life of mud pump liner will affect the oil drilling system directly.
Because the working surface of liner is in contact with the high temperature and high pressure oil gas, it should not only have high strength and rigidity, but also must be high temperature resistance, corrosion resistance and wear resistance.
1. Liner Classification
There are mainly two kinds of liners: bi-metal liner (high chrome liner) and zirconia ceramic liner.
Bi-metal Liner
Bi-metal liner is the most widely used in oil drilling system, and is also the most important part of mud pump fluid end.
It consists of two parts: outer hull and inner sleeve. The outer hull is forged by high quality 45# steel, and the inner sleeve is casting by high chromium cast iron.
Advantage:
1) . Inner sleeve HRC≥62
2) . High finish for inner sleeve, can reach Ra0.05, far higher than API standard.
3) . The service life can be more than 800 hours.
2. The Process Flow of Liner
Inner Sleeve:
Material inspection→centrifugal casting→annealing→rough turning of outer race→rough turning of inner hole→finish turning of outer race→quenching→non-destructive test→assembly with outer hull
Outer Hull:
Material inspection→forging→rough turning of outer race→rough turning of inner hole→normalizing→finish turning of inner hole→heat treatment→assembly with inner sleeve→inner hole grinding→inner hole honing→finish turning
3. Install Caution
1) Don’t throw and impact the mud pump liner. If the liner needs to be inverted, it should be done slowly.
2) Please ensure the coaxiality between the metal parts of piston and the inner wall of liner.
3) Don’t hit the liner with a hammer directly, if you need to hit, the wood or other materials should be placed on the liner.
4) When the equipment is out of service for a long time under 0℃ in winter, the mud should be released to prevent the inner sleeve of liner from freezing and cracking.
