Machine the double metal cylinder of drilling mud pump

Mud pump is also known as the heart in the drilling system. while the mud pumps cylinder is the important and easy wear out parts in mud pump fluid end, the cylinders life directly effect the mud pumps life. Moreover the working surface of the cylinder was contact with the gas which has high temperature and high pressure, there are piston ring running reciprocating motion on the surface, those require the cylinder of mud pump has a better sufficient strength and rigidity, and also must have high temperature resistance, corrosion, wear-resistant properties.

Part 1 The type and advantage of the drilling mud pumps cylinder:
At present, commonly there are those types of cylinder: single metal cylinder, double metal cylinder, ceramic liner, nickel-based alloy cylinder liners. Wherein the double metal cylinder is the most widely used one, also it is one which is the largest amount of mud pump fluid end components.

Double metal cylinder includes inner and outer cylinder, The outer cylinder was made of high-quality carbon steel hot press which molding, having a tensile strength greater than 900000psi. Inner cylinder was made of high chrome cast iron casting, hardness can reach more than HRC62 after the heat treatment, which can withstand pressure 7000psi from mud, so the requirement was more strictly with the surface and inner hole size of inner and outer cylinder.

Part 2 Processing technology and heat treatment of the double metal mud pump cylinder for drilling

1.Outer cylinder: Inspection of the raw material----process the rough----inner bores roughing----thermal loading (and inner sleeve thermal loading)----boring inside----finishing grinding--- finishing turning
2.Inner sleeve: centrifugal casting----annealing----roughing excircle----inner bores roughing---half finishing excircle----quenching----NDT---shrinkage fitting (with outer cylinder)
3.Heat treatment classifying: normalizing, annealing, quenching, tempering, shrinkage fitting(shrinkage fitting means burned at a temperature of 450 ℃ -500 ℃ for 5-6 hours, then 100% inspection and pressure  test after 24 hours cooling). You can choose a different heat treatments depending on the different manufacturers process technology.

Part 3 Most suitable materials for machining drilling double metal mud pump cylinder sleeve
At beginning, we said the hardness reach HRC62 or more after heat treatment, it has a high hardness and difficult to process, also requires a high dimensional accuracy. Currently people use carbide tool ,ceramic tools and CBN tools to machine the ferrous metal.

Why CBN tools is the best choice when people machine the drilling double metal mud pump cylinder sleeve, the reasons as follows:

(1) carbide cutting tools are only suitable for machining ferrous materials hardness HRC45 or less due to its performance;

(2) ceramic cutting tools suit for machining ferrous metal materials which hardness was between the HRC45 to HRC55, and finishing process which the machining allowance is smaller.

(3)As the hardness of the cubic boron nitride(CBN) tools is only to diamond tools’ ,They both called super-hard tools, there is a good effect to machining ferrous materials which hardness above HRC45 with CBN tools.
Through Halnn superhard material company’s steady effort more than ten years in this field, She become the best-known material processing tools brand, From Halnn was founded, she continued to provide the tools which were high-efficiency, high-quality, high-performance for the high hardness and difficult to machine tool materials in the field, She enjoyed a high reputation in the field of hard materials processing tool, she was the world-class leader.

Halnn superhard has the professional cubic boron nitride cutting tool for machining drilling mud pump cylinder, specific details as follows.

Part 4 Appliccation Case of Halnn superhard cubic boron nitride tools processing drilling mud pump cylinder liners parameters

Workpiece Name:	Cylinder liner of mud pump
Heat treatment	Surface hardening
Work piece material	High chromium cast iron:
Hardness	HRC60-65
Work piece dimension	Diameter:178mm,Thickness:5mm,Lenth:450~600mm
Machining parts:	The outer, chamfered
CBN Insert Grade	Halnn BN-S30
Arbor Model	CCLNR2525M1207
Inserts Model	CNMN120712-8S
Cutting parameters	Vc=90-120m/min, Fr = 0.25mm, ap=2mm
Durability	9pieces/edge

If you would like to know more details ,please feel free to contact with us halnntools@gmail.com ,whatsapp:+8618695866134