In cryogenic applications such as liquefied natural gas (LNG), air separation units, and liquid hydrogen/oxygen storage and transport, temperatures can drop as low as -196°C. At such extreme low temperatures, ordinary metals become brittle, sealing materials shrink or even crack, and the risk of valve leakage increases dramatically. How can long-term reliability and zero leakage be ensured in such extremely cold environments? TONGBALL provides the answer: specialized low-temperature material selection + ultra-precision machining + cryogenic testing validation.
Core Challenges of Cryogenic Service for Valves
In media such as liquid nitrogen and LNG at -196°C, valves face three major technical challenges:
1. Low-Temperature Embrittlement of Materials
Common stainless steel (e.g., 304) undergoes martensitic transformation at low temperatures, resulting in a sharp drop in toughness and an increased risk of cracking. Differences in the coefficient of thermal expansion between the sealing surface coating and the substrate may lead to coating spalling.
2. Leakage Due to Sealing Surface Contraction
Metal components such as the ball, seat, and body contract unevenly at low temperatures, increasing the gap between sealing surfaces. Conventional sealing structures may consequently fail.
3. Stem Packing Failure
Conventional PTFE or graphite packing shrinks and hardens at low temperatures, increasing frictional resistance and even losing its sealing capability, leading to external leakage of the medium.
TONGBALL's Cryogenic Technology Solutions
1. Professional Low-Temperature Material Selection
TONGBALL selects specialized materials for cryogenic service to ensure stability across the full range from -196°C to ambient temperature:
Body / Bonnet: F304L, F316L (low-carbon austenitic stainless steel with excellent low-temperature toughness)
Ball / Seat: F304L/F316L + cryogenic-specific coating, or 9Ni steel (9% nickel steel, which maintains good toughness at -196°C)
Stem: F304L, F316L, Inconel 625 (high strength and corrosion resistance)
Sealing Surface: Cryogenic-specific Stellite alloy or PVD coating, matched to the thermal expansion coefficient of the substrate
TONGBALL's material system covers the complete temperature range from -196°C cryogenic to 1200°C ultra-high temperature, ensuring precise material-to-application matching.
2. Ultra-Precision Machining and Cryogenic Gap Design
The key to cryogenic valves is that a valve assembled at ambient temperature must still seal reliably at low temperatures.
TONGBALL's core technologies include:
Cryogenic gap pre-compensation: Precise calculation of ambient assembly gaps based on material thermal expansion coefficients to ensure tight sealing surface contact at low temperatures
Ball sphericity ≤0.005 mm: Extreme roundness guarantees uniform ball-to-seat contact at low temperatures
Sealing surface roughness Ra ≤0.1 μm: Mirror-like finish ensures zero leakage even at low temperatures
Ultra-precision machining of stem and packing mating surfaces: Reduces friction and leakage risk at low temperatures
3. Full-Process Cryogenic Testing Validation
TONGBALL performs strict low-temperature tests on every batch of cryogenic valve components:
✅ Liquid nitrogen immersion test: Assembled ball valve components are immersed in liquid nitrogen (-196°C) and subjected to pressure to verify sealing performance
✅ Thermal cycling test: Repeated cycling between -196°C and ambient temperature to verify material and sealing stability
✅ Cryogenic helium leak test: A cryogenic helium mass spectrometer is used to detect micro-leakage with sensitivity down to 10⁻⁶ Pa·m³/s
✅ Low-temperature coating adhesion test: Verifies the bond strength of coatings under extreme low temperatures
"In cryogenic service, a valve that passes inspection at ambient temperature may not be suitable for low-temperature operation."
—— TONGBALL Technical Director
"Every one of our cryogenic valve components undergoes real liquid nitrogen environment validation to ensure reliability throughout the entire lifecycle, from assembly to service."
Typical Application Scenarios
TONGBALL's cryogenic valve components have been successfully applied in multiple low-temperature fields:
LNG terminals and liquefaction plants: -162°C LNG media – balls, seats, stems
Air separation units: -196°C liquid oxygen and liquid nitrogen – cryogenic ball valve components
Cryogenic storage and transport: Liquid hydrogen, liquid helium, and other ultra-low temperature media – valve components
Liquefied Petroleum Gas (LPG) : -42°C propane and propylene media
Summary: Three Pillars of TONGBALL Cryogenic Technology
Materials: F304L/F316L, 9Ni steel, Inconel 625, and other low-temperature-specific materials
Precision: Ball sphericity ≤0.005 mm, sealing surface roughness Ra ≤0.1 μm, cryogenic gap pre-compensation
Validation: -196°C liquid nitrogen immersion test, thermal cycling test, helium mass spectrometry leak detection
With the integrated technology system of cryogenic materials + ultra-precision machining + cryogenic testing, TONGBALL Valve provides zero-leakage, long-life ball valve core components for LNG, air separation, cryogenic storage, and transport industries.
If you are facing challenges with valve selection for cryogenic projects such as LNG terminals, air separation units, or liquid hydrogen storage, TONGBALL's cryogenic technology solution is worthy of your trust.
