fully welded ball valve is a type of ball valve where the valve body is manufactured as a single, fully welded piece, without body flanges or bolts. This construction enhances strength, eliminates external leakage paths, and makes it particularly suitable for long-term buried or high-pressure applications, especially in pipelines for oil, gas, and district heating systems.


fully welded ball valve is a robust, maintenance-free valve with a welded body that eliminates external leakage. Its main advantages are high safety, long life, and suitability for underground and high-pressure pipelines.
 

Description

Structure of fully welded ball valve

Valve Body – Fully welded steel structure, seamless, no body flanges or bolts.
Ball – Precision machined and often hard-chrome or electroless nickel plated for durability.
Stem – Typically anti-blowout design, connected to the ball with a trunnion or floating mechanism.
Seats – Soft-seated (PTFE, reinforced PTFE) or metal-seated depending on medium and temperature.
Sealing Design – Often dual sealing (primary soft seat + secondary metal-to-metal seat).
Actuation – Operated manually with a lever/gearbox or automated using pneumatic, hydraulic, or electric actuators.
 

Features & Performance of fully welded ball valve

No External Leakage: Welded body removes potential leak paths from flanged joints.
High Strength & Pressure Resistance: Suitable for medium- to high-pressure pipelines.
Long Service Life: Protected ball and seat design, often with self-lubricating seats.
Maintenance-Free: Since the body cannot be opened, it’s designed for long-term maintenance-free operation.
Buried/Underground Use: Excellent corrosion resistance with external coatings, ideal for buried pipelines.
Fire-Safe Design: Many designs comply with API 607 / ISO 10497 fire-safe standards.
Anti-Blowout Stem: Increases safety in high-pressure service.
Low Torque Operation: Seats often designed to reduce operating torque, enabling easier actuation.

Application Cases of fully welded ball valve

Oil & Gas Pipelines
Long-distance natural gas transmission lines
Crude oil and refined product pipelines
Underground installations requiring zero leakage
District Heating & Cooling Systems
Buried valves in hot water or steam pipelines
Heating networks in urban systems
Petrochemical Plants
High-pressure process lines requiring reliability and safety
Power Industry
Steam and condensate pipelines
Cooling water lines
City Gas Distribution
Underground gas pipeline distribution networks

Expanded view of fully welded ball valve 
expanded view of fully welded ball valve

Bill of Fully welded Ball Valve materials 
 

No. name of Part Materials
1 Body A350 LF2 A182 F316 ASTM  A105
2 Closure A350 LF2 A182 F316, A351, CF8M ASTM  A105
3 Stem A350 LF2+ENP 316 SS, 17-4 PHSS, 410 SS A182 F6a
4 Seat Ring A350 LF2+ENP 316 SS, 410 SS ASTM  A105+ENP
5 Ball A350 LF2+ENP A182F316, A351, CF8M, 410 SS ASTM  A105+ENP
6 Seat Insert Devlon, Nylon, PEEK, RTFE
7 Trunnion A350 LF2 316 SS, 410 SS ASTM  A105
7-1 Trunnion Block A350 LF2 316 SS, 410 SS ASTM  A105
7-2 Trunnion Block Pin 410 SS 316 SS, 410 SS ASTM  A105
8 Gland A350 LF2 316 SS, 410 SS ASTM  A105
9 Adapter Plate A350 LF2 316 SS, 410 SS ASTM  A105
10 Stem O-ring/ Lipseal Low Temp HNBR /Viton AED
Low Temp HNBR /Viton AED
Low Temp HNBR /Viton AED
Low Temp HNBR /Viton AED
Low Temp HNBR /Viton AED
Low Temp HNBR /Viton AED
Low Temp HNBR /Viton AED
11 Stem O-ring
12 Gland O-ring
13 Seat O-ring/Lipseal
14 Seat Subseal
15 Closure O-ring
16 Trunnion O-ring
17 Backup Ring PTFE
18 Gland Seal Low Temp HNBR /Viton AED
19 Body Seal Low Temp HNBR /Viton AED
20 Trunnion Seal Low Temp HNBR /Viton AED
21 Stem Packing Graphite
22 Seat Spring Inconel X-750
23 Bearing PTFE, Carbon Steel PTFE, 316SS PTFE, Carbon
24 Thrust Washer PTFE, Carbon Steel PTFE, 316SS PTFE, Carbon
25 Sealant Fitting Carbon Steel, SS Ball Check 316SS, SS Ball Check Carbon Steel
26 Socket Bolt A320 L7M A193 B8/B8M ASTM A193-B7
27 Socket Cap Screw A320 L7M A193 B8/B8M ASTM A194-2H
28 Stud Bolt A320 L7M A193 B8 ASTM A193-B7
29 Hex Nut A194 7M A194 8 ASTM A194-2H
30 Grounding Pin Stainless Steel
31 Grounding Spring Inconel X-750
32 Key Carbon Steel Stainless Steel Carbon Steel
33 Dowel Pin Carbon Steel Stainless Steel Carbon Steel
34 Relief Plug Carbon Steel Stainless Steel Carbon Steel
35 Drain Plug Carbon Steel Stainless Steel Carbon Steel
36 Mounting Plate Carbon Steel Stainless Steel Carbon Steel
37 Gear Operator Ductile Iron Case, Carbon Steel Worm Gear
38 Hand Wheel Carbon Steel, Ductile Iron
note: Materials also available in F321, F347, F51, F53, monel, inconel, incolloy and hastelloy.  Metal-to-metal seated ball valve designs are available upon   request.

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