Flow Control Choke Valve Stem And Seat Flow Control System With
Stable Chemical Properties
Valve is assembled product. Valve external parts and Valve trim
parts such as Body, Bonnet, Disk/wedge, Seat, Steam, Gland Packing
/ Stud & Bolt
/ Gasket / Handwheel are all manufactured independently and
assembled in valve factory.
Tungsten Carbide Materials Grade As Below:
| Zonco Grade | Density
(g/cm3) | Hardness (HRA) | TRS
(≥N/mm²) |
| ZK11 | 14.2-14.4 | 87.1 | 2600 |
| ZK15 | 13.95-14.15 | 87 | 2600 |
| ZK20 | 13.45-13.65 | 83.5 | 2600 |
| ZK06 | 14.8-15 | 90 | 2100 |
| ZK06A | 14.85-15 | 91 | 2000 |
| ZK08 | 14.65-14.85 | 89.5 | 2000 |
| ZY20C | 13.4-14.6 | 82.5 | 2700 |
What is Valve Trim?
The removable and replaceable internal parts of the valve that come
in contact with the flow medium are collectively known as valve
trim. Disc, valve seat, and stem are common for all the valve.
Valve Trim components will change with types of valve. Valve
specific trim includes back seat, glands, spacers, guides,
bushings, retaining pins and internal springs. Here in the image,
you can see the gate valve trim parts. Because of the trim parts,
disk movement and flow control are possible.
Seat
The seat provides the seating surface for the disk. Here, you can
see the gate valve seat in the above image. A valve may have
multiple seats. In the case of globe valve and swing-check valve,
there is one seat. Whereas, a gate valve and ball valve has two
seats; one on the upstream side and the other on the downstream
side.
The valve leakage rate is directly proportional to the
effectiveness of the seal between the valve disc and seat(s). Valve
seats may be integral or replaceable rings. Valves are generally
provided with screwed, welded, or integrally cast or forged seat
and hardened by heat treatment or by hard facing of Stellite weld
overlay. A fine surface finish of the seating area is necessary for
proper sealing. Some ball valve & plug valve used the non-metallic
seat for non-critical services. Valve manufacturers have developed
several designs of combination valve seats involving elastomer and
metal seats that are effective in achieving the desired leak
tightness, which cannot be achieved only by metal seats.
Stem
The stem connects the actuator and disk. It moves and positions the
valve disk. The valve stem transports the required motion to the
disc, plug, or the ball for opening, closing or positioning the
valve. The stem connects actuator, handwheel or the lever of the
valve at one end and the disc on the other end. In gate and globe
valves, linear motion of the disc open or close the valve, while in
the plug, ball, and butterfly valves, the disc rotates to open or
shut the valve. Stems are typically forged from stainless steel and
connected to the disk by threaded or welded joints.
Products show
| Common Alloy Grades, Ghysical Mechanical Properties And Recommended
Application |
| Grade | WC% | Co/Ni % | Physical and mechanical properties | Grain size (μm) | Recommended application |
| Density (g/cm3) | TRS (N/mm2) | Hardness (HRA) |
| ZG01 | 100 | 0 | 15.3-15.5 | 1200 | 95.5 | 0.3 | Ultra-high hardness, high wear resistance, anti-corrosion, with
certain anti-destructive ability |
| ZG04X | 96 | 4 | 15.0-15.2 | 1600 | 92.8 | 0.8-1.0 | Suitable for drawing die, non-ferrous metal wire drawing and
wear-resistant parts |
| ZG06 | 94 | 6 | 14.8-15.1 | 2500 | 90.0 | 1.2 | Good abrasion resistance, good compression resistance, suitable for
wear-resistant parts that resist abrasion and high pressure. |
| ZG06X | 94 | 6 | 14.8-15.1 | 2400 | 91.5 | 1.0 | Superio wear resistance,good comprehensive properties,suitable for
making non-standard structure components with higher wear
resistance. |
| ZG06A | 94 | 6 | 14.8-15.1 | 2150 | 92.5 | 0.6-0.8 |
| ZG08 | 92 | 8 | 14.6-14.9 | 2700 | 89.0 | 1.2-1.6 | Good general performance, used for general wear parts, molds,
general tools, etc. |
| ZG10.2 | 90 | 10 | 14.3-14.6 | 3800 | 91.7 | 0.7 | Good general performance, suitable for casing and oil nozzle
products |
| ZG11 | 89 | 11 | 14.3-14.7 | 2800 | 88.5 | 1.2-1.6 | Anti-wear, anti-erosion, good comprehensive mechanical strength,
suitable for wear-resistant parts in the petroleum, chemical and
mechanical industries. |
| ZG12X | 88 | 12 | 14.2-14.5 | 3000 | 89.5 | 1.0-1.2 | Anti-erosion, good comprehensive mechanical strength, suitable for
impact-resistant wear-resistant parts, molds, and roller rings. |
| ZG15 | 85 | 15 | 13.8-14.2 | 3000 | 86.5 | 1.2-1.6 |
| ZG15X | 85 | 15 | 13.8-14.2 | 4500 | 89.0 | 0.7 | Excellent wear resistance and toughness,it is suitable for making
integral stamping dies, anti-vibration toolholders, etc. |
| ZG20 | 80 | 20 | 13.4-13.8 | 3100 | 85.0 | 1.0 | Excellent wear resistance and toughness |
| ZN06 | 94 | 6 | 14.5-14.9 | 2000 | 90.0 | 1.2 | Non-magnetic alloy, suitable for sealing ring, non-magnetic
wear-resistant parts and corrosion-resistant parts. |
| ZN09 | 91 | 9 | 14.3-14.6 | 2300 | 89.0 | 1.2-1.6 |
| ZN11 | 89 | 11 | 14.0-14.3 | 2600 | 88.0 | 1.2 |
