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Molybdenum Nuts

Molybdenum nuts possesses a very high melting point of 2620°C, a low coefficient of thermal expansion and a high level of thermal conductivity. Because molybdenum Nuts have the ability to withstand extremely high temperatures without changing shape, expanding or softening significantly, they are ideal for high strength / high temperature applications that are shielded from oxygen. Exposing molybdenum nuts to oxygen above 600°C will cause them to readily oxidize.

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Molybdenum Nuts find their way into high temperature vacuum furnaces, glass production, military and space applications where oxygen is not present.

Extreme high temperature stability & strength
Maintains strength at elevated temperatures
Low distortion at high temperature
Molybdenum must be used in vacuum or inert gas at high temperatures

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RAYCHIN LIMITED

Name: Molybdenum Nuts
SKU: 0

Molybdenum Nuts · Hex / Lock / Jam / Flange · Inch & Metric · Pure Mo / TZM / MoLa

Molybdenum Nuts: Ultra-High Purity Refractory Metal Nuts for Extreme Temperature Environments

Pure Mo (≥99.95%) | TZM (Mo-Ti-Zr-C) | MoLa (Mo-La₂O₃) | ASTM B386 / B387 | ISO 4032 / DIN 934

RAYCHIN LIMITED is a leading manufacturer of Molybdenum Nuts – precision-engineered fasteners produced from refractory molybdenum and its alloys, delivering exceptional high-temperature strength, thermal stability, and resistance to creep in extreme environments. With a melting point exceeding 2600°C (4700°F) and the ability to withstand temperatures up to 1700°C in vacuum or reducing atmospheres, molybdenum nuts retain structural integrity where conventional fasteners fail. Our comprehensive product line includes molybdenum hex nuts, lock nuts, jam nuts, flange nuts, and coupling nuts – all manufactured to the highest precision standards. Available grades include Pure Molybdenum (≥99.95%), TZM alloy (Mo-0.5Ti-0.08Zr-0.02C), and Molybdenum Lanthanum (MoLa) with enhanced recrystallization temperature. Our portfolio includes all standard and custom configurations manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS standards, including ASTM B386/B387, ISO 4032, ISO 4033, ISO 4034, DIN 934, and ASME B18.2.2. Whether you require molybdenum nuts for high-temperature vacuum furnaces, semiconductor sputtering equipment, sapphire crystal growth systems, or aerospace propulsion components, RAYCHIN delivers precision, quality, and full traceability. All mechanical properties are presented in MPa and ksi (kilopound per square inch).

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Molybdenum Nuts – Design & Configurations

Hex Nuts & Heavy Hex Nuts

Molybdenum hex nuts are the most common type for general bolting, designed to match the strength of molybdenum bolts and prevent thread stripping at extreme temperatures. Available in finished hex (ASME B18.2.2, ISO 4032, DIN 934) and heavy hex series (ASME B18.2.2, ISO 4033). Precision tapped with class 2B/6H threads from M1.6 to M64 (#0 to 2-1/2"). Ideal for high-temperature furnace assemblies, heat shields, and secure connections in ultra-high-vacuum (UHV) environments.

Lock Nuts (All-Metal)

Molybdenum lock nuts provide prevailing torque to prevent loosening under extreme thermal cycling and vibration in high-temperature environments. All-metal flexloc style with segmented collar creates locking action suitable for applications up to 1700°C in vacuum or inert atmospheres. Available in hexagonal and thin configurations, certified to prevailing torque standards. Essential for semiconductor sputtering equipment and high-vibration furnace components.

Jam Nuts & Thin Nuts

Molybdenum jam nuts (thin height) are used for locking adjustments in confined spaces and for jamming against standard nuts to prevent loosening under thermal expansion. Manufactured to ASME B18.2.2 (jam) and ISO 4035 (metric thin nuts). Ideal for precision furnace instrumentation, sensor mounts, and applications with limited axial space while maintaining corrosion resistance at elevated temperatures.

Flange Nuts

Molybdenum flange nuts feature an integrated flange that distributes load and eliminates washers, with increased bearing area for critical high-temperature applications. Available in ASME B18.16.6 (inch) and ISO 4161 (metric) configurations. Ideal for subsea components, vacuum furnace door seals, and heavy-duty industrial machinery where vibration resistance and thermal stability are essential.

Coupling Nuts & Extended Height Nuts

Molybdenum coupling nuts (long nuts) are used to connect two threaded rods or for tensioning applications in tight spaces. Available in various lengths and diameters from M2 to M64. Custom lengths and special end configurations available. Used extensively in crystal growth furnaces, glass melting electrode assemblies, and semiconductor processing equipment where exposure to high pressure and extreme temperatures is constant.

Alloy Grades: TZM & MoLa

TZM alloy nuts (Mo-0.5Ti-0.08Zr-0.02C) offer higher recrystallization temperature (~1400°C), improved strength, and creep resistance compared to pure Mo. MoLa alloy nuts (Mo doped with La₂O₃) exhibit enhanced ductility and high-temperature stability. Both alloys available across all nut types for applications exceeding 1400°C in vacuum or reducing atmospheres.

Aerospace & Military Standards

Our molybdenum nuts meet applicable sections of NAS1802 (hex nuts), NASM 21042 (lock nuts), MS21042, MS21044, MS21045, MS35649, MS35650, and AN315/AN316. Full compliance with ASTM B386 (plate/sheet/foil) and ASTM B387 (rod/bar/wire) for material and mechanical properties. Silver plating per AMS 2410 available for anti-galling. Cleanroom packaging available for semiconductor and aerospace applications.

Custom & Non-Standard Nuts

Need special thread sizes, non‑standard heights, proprietary locking features, or unique drive configurations? RAYCHIN engineers design and produce custom molybdenum nuts to your exact specifications – any grade (pure Mo, TZM, MoLa), any condition (stress relieved, recrystallized), with full material traceability. Prototype to production volumes supported. In-house metallurgical laboratory ensures optimal performance for your application.

Critical Applications of Molybdenum Nuts

High-Temperature Vacuum Furnaces

Molybdenum nuts are essential in vacuum furnace construction, including hot zones, heating element supports, heat shields, and hearth assemblies. They maintain structural integrity at temperatures exceeding 1700°C (3090°F) in vacuum or inert gas environments where superalloys fail. Used in sintering furnaces, brazing furnaces, and annealing furnaces. Hex nuts secure heating elements and heat shields, while coupling nuts connect threaded rods in furnace support structures.

Semiconductor & Sputtering Equipment

Molybdenum nuts in semiconductor manufacturing equipment, including sputtering targets, PVD chambers, ion implanters, and wafer processing systems. Molybdenum's low coefficient of thermal expansion (5.1 x 10⁻⁶ /K), high thermal conductivity (138 W/m·K), and non-contaminating properties (no outgassing) make it ideal for ultra-high-vacuum (UHV) environments. Essential for securing electrodes, shields, and process kits. Lock nuts provide vibration resistance in rotating sputtering systems.

Sapphire Crystal Growth & Glass Melting

Molybdenum nuts used in sapphire crystal growth furnaces (Kyropoulos, Czochralski) and glass melting electrodes. Molybdenum withstands molten glass corrosion and extreme temperatures required for LED sapphire substrate production. Nuts secure crucible assemblies, heat shields, and electrode holders in aggressive molten environments. Flange nuts provide enhanced load distribution in high-pressure glass melting systems.

Aerospace & Defense

Molybdenum nuts in rocket engine components, nozzle assemblies, re-entry vehicle heat shields, and supersonic aircraft skin elements. Molybdenum alloys maintain strength at extreme temperatures where other metals would soften or melt. Used in thrust vector control systems and high-temperature structural joints. Lock nuts prevent loosening under extreme vibration during launch and re-entry. Jam nuts provide precise adjustments in flight control mechanisms.

Nuclear Engineering

Molybdenum nuts in nuclear reactors, particle accelerators, and experimental fusion devices. Molybdenum exhibits excellent resistance to radiation damage and retains mechanical properties under neutron irradiation. Used for fuel cladding supports, control rod mechanisms, and plasma-facing component fasteners. Coupling nuts provide secure connections in cooling systems exposed to liquid metal coolants (lithium, sodium).

Medical & X-ray Equipment

Molybdenum nuts in X-ray tube assemblies, radiation shielding components, and medical isotope production equipment. Molybdenum's high atomic number and thermal properties make it suitable for X-ray targets and collimators. Nuts secure targets and cathodes under high-voltage, high-temperature operation. Cleanroom packaging available for medical device applications requiring strict contamination control.

International Standards & Global Designations – Molybdenum Nuts

RAYCHIN LIMITED manufactures molybdenum nuts from vacuum arc melted (VAR) or powder metallurgy (PM) material conforming to the most widely used national and international specifications. All material is traceable to the mill.

Designation	Standard / Specification	Description
Pure Molybdenum	Mo ≥99.9% – ≥99.95%	Unalloyed molybdenum, highest purity available; excellent thermal conductivity, low vapor pressure
ASTM B386 / B386M	Standard Specification for Molybdenum and Molybdenum Alloy Plate, Sheet, Strip, Foil, and Ribbon	Covers grades 360 (vacuum arc melted pure Mo), 361 (powder metallurgy pure Mo), 363 (TZM), 364 (powder metallurgy TZM), 365 (low C Mo), 366 (Mo-30W)
ASTM B387 / B387M	Standard Specification for Molybdenum and Molybdenum Alloy Bar, Rod, and Wire	Primary material specification for molybdenum fastener stock; covers same grades as B386
TZM Alloy	Mo-0.5Ti-0.08Zr-0.02C	Molybdenum alloy with titanium, zirconium, carbon for enhanced strength and recrystallization temperature
MoLa (Mo-La₂O₃)	Mo with 0.3-0.6% Lanthanum Oxide	Dispersion-strengthened molybdenum with improved ductility and high-temperature stability
ISO 4032:2012	Hexagon regular nuts (style 1) – metric series	Dimensional standard for molybdenum hex nuts, M1.6 to M64
ISO 4033	Hexagon high nuts – metric series	Dimensional standard for heavy hex nuts
ISO 4034	Hexagon thin nuts – metric series	Dimensional standard for jam nuts
DIN 934	Hexagon nuts – metric series	German standard for hex nuts, interchangeable with ISO 4032
ASME B18.2.2	Nuts for General Applications (inch series)	Dimensional standards for inch-series nuts including hex, jam, slotted nuts
JIS B 1181	Hexagon nuts – metric series	Japanese Industrial Standard for hex nuts
AMS 7847 / AMS 7848	TZM bar and rod specifications	Aerospace material specifications for TZM alloy

ASTM B386 ASTM B387 Pure Mo 99.95% TZM MoLa ISO 4032 DIN 934 ASME B18.2.2 JIS B 1181 NAS1802 MS21042

Chemical Composition (Weight %) – Molybdenum Alloys for Nuts

Our molybdenum nuts are produced from vacuum arc melted (VAR) or powder metallurgy (PM) material conforming to ASTM B386/B387 and industry standards.

Pure Molybdenum (Grade 360 / 361) – Mo ≥99.95%

Element	Min %	Max %	Typical
Molybdenum (Mo)	99.9	Balance	99.95
Iron (Fe)	—	0.010	0.004
Nickel (Ni)	—	0.005	0.002
Silicon (Si)	—	0.010	0.0013
Carbon (C)	—	0.030	0.0028
Oxygen (O)	—	0.0070	0.005
Nitrogen (N)	—	0.002	0.002
Aluminum (Al)	—	0.002	0.0005
Calcium (Ca)	—	0.002	<0.001
Magnesium (Mg)	—	0.002	<0.0005

TZM Alloy (Grade 363 / 364) – Mo-0.5Ti-0.08Zr-0.02C

Element	Min %	Max %	Typical
Molybdenum (Mo)	Balance	Balance	~99.0
Titanium (Ti)	0.40	0.55	0.50
Zirconium (Zr)	0.06	0.12	0.08
Carbon (C)	0.01	0.04	0.02
Iron (Fe)	—	0.010	0.005
Nickel (Ni)	—	0.005	0.002
Silicon (Si)	—	0.010	0.005
Oxygen (O)	—	0.0030	0.002
Nitrogen (N)	—	0.002	0.001

MoLa Alloy (Mo with Lanthanum Oxide)

Element	Min %	Max %	Typical
Molybdenum (Mo)	Balance	Balance	~99.5
Lanthanum Oxide (La₂O₃)	0.3	0.6	0.4
Other impurities	—	0.10	<0.05

Metallurgical note: Molybdenum is a refractory metal with a body-centered cubic (BCC) crystal structure. Pure molybdenum nuts are typically supplied in stress-relieved condition (recrystallization temperature ~1100°C) or soft/annealed condition. TZM alloy offers significantly higher recrystallization temperature (~1400°C) and improved creep strength through carbide dispersion strengthening. MoLa (lanthanated molybdenum) maintains ductility after high-temperature exposure due to oxide dispersion pinning grain boundaries. All molybdenum nuts should be handled with care due to limited ductility at room temperature, becoming more ductile above ductile-to-brittle transition temperature (DBTT).

Complete Mechanical & Physical Properties – Molybdenum Nuts (MPa / ksi)

Molybdenum nuts are supplied in various conditions (hard/stress relieved, soft/annealed) per ASTM B387. Data represent typical values based on industry standards.

Mechanical Properties – Pure Molybdenum Nuts

Condition	Tensile Strength (MPa)	Tensile Strength (ksi)	Yield Strength 0.2% (MPa)	Yield Strength 0.2% (ksi)	Elongation (%)	Hardness (Vickers)
Hard (Stress Relieved)	620-690	90-100	550-620	80-90	10-20	250
Soft (Recrystallized/Annealed)	485-550	70-80	415-450	60-65	20-30	200
Typical (Pure Mo)	515	75	380	55	15	200-250

Mechanical Properties – TZM Alloy Nuts

Condition	Tensile Strength (MPa)	Tensile Strength (ksi)	Yield Strength 0.2% (MPa)	Yield Strength 0.2% (ksi)	Elongation (%)	Hardness
Stress Relieved	860-1035	125-150	690-860	100-125	8-15	300 HV
Recrystallized	620-760	90-110	550-620	80-90	15-25	230 HV

Physical Properties – Molybdenum

Property	Metric	Imperial	Notes
Density	10.22 g/cm³	0.369 lb/in³	Pure Mo
Density (TZM)	10.16-10.20 g/cm³	0.367-0.368 lb/in³	Slightly lower due to alloying
Melting Point	2617-2623°C	4743-4753°F	Pure Mo
Boiling Point	4612-4639°C	8334-8382°F
Elastic Modulus (E)	324-329 GPa	47.0-47.7 x 10³ ksi	Stress relieved condition
Poisson's Ratio	0.293-0.31	0.293-0.31
Thermal Expansion (20-100°C)	5.1-5.2 x 10⁻⁶ /K	2.8-2.9 x 10⁻⁶ /°F	Very low CTE
Thermal Conductivity	138-142 W/m·K	960-985 BTU·in/(hr·ft²·°F)	Excellent conductivity
Electrical Resistivity	5.7 µΩ·cm	2.24 µΩ·in	At 20°C
Specific Heat	251 J/kg·K	0.06 BTU/lb·°F	At 25°C

High‑Temperature Performance of Molybdenum Nuts

Molybdenum and its alloys are renowned for exceptional high-temperature strength and stability. Pure molybdenum maintains useful mechanical properties up to 1700°C (3090°F) in vacuum or reducing atmospheres, with TZM extending capability further through carbide strengthening. However, molybdenum oxidizes rapidly above 600°C in air, forming volatile MoO₃, limiting use to vacuum, inert gas, or reducing environments unless protected by coatings.

Elevated Temperature Capabilities

Property	Pure Molybdenum	TZM Alloy	MoLa Alloy
Max Service Temp (vacuum/inert)	1700°C (3090°F)	1400-1500°C (2550-2730°F)	1700°C (3090°F)
Recrystallization Temp	1100°C (2010°F)	1400°C (2550°F)	1300-1500°C
Creep Resistance	Good	Excellent	Very Good
Tensile Strength @ 1000°C	~300 MPa (43 ksi)	~450 MPa (65 ksi)	~350 MPa (51 ksi)
Oxidation Onset in Air	600°C (1110°F) – formation of volatile MoO₃

High-Temperature Comparison – Molybdenum vs. Stainless Steel

Property	Molybdenum (Pure)	SUS304 Stainless Steel	Notes
Tensile Strength (MPa)	515-690	≥520	Comparable at RT
Yield Strength 0.2% (MPa)	380-620	≥205	Mo much stronger
Elongation (%)	10-20	≥40	SS more ductile
Specific Gravity	10.2	7.93	Mo denser
Elastic Modulus (GPa)	327	193	Mo 70% stiffer
Thermal Conductivity (W/m·K)	142	17	Mo 8x higher
Thermal Expansion (x10⁻⁶/K)	5.1	17.3	Mo much lower
Max Service Temp (air)	600°C (oxidizes)	~900°C	SS higher in air
Max Service Temp (vacuum)	1700°C	~900°C	Mo superior in vacuum

Note: All molybdenum nuts must be used in vacuum, inert gas, or reducing atmosphere (H₂) above 600°C to prevent catastrophic oxidation. For air applications, protective coatings (MoSi₂, Al₂O₃, Y₂O₃) may be applied.

Corrosion Resistance of Molybdenum Nuts

Molybdenum exhibits excellent resistance to many corrosive media, particularly in reducing environments and in the absence of oxidizing agents. However, rapid oxidation occurs in air above 600°C. Its stability in various chemical environments makes it suitable for chemical processing equipment and research applications.

Acid Resistance: Excellent resistance to hydrochloric acid (HCl), sulfuric acid (H₂SO₄) at moderate temperatures, and phosphoric acid (H₃PO₄). Resists most non-oxidizing mineral acids. Rapid attack in nitric acid (HNO₃) and other oxidizing acids.
Alkalis: Generally good resistance, but can be attacked by fused alkalis. Resistant to many molten salts.
Liquid Metals: Excellent resistance to liquid lithium, sodium, potassium, and bismuth, making it valuable in nuclear coolant systems.
Halogens: Resistant to fluorine, chlorine, and bromine at moderate temperatures; attacks at higher temperatures.
Oxidation: Forms volatile MoO₃ above 600°C in air; requires protective atmosphere or coating for high-temperature air service.
Hydrogen: Excellent resistance to hydrogen attack even at high temperatures (unlike steel).
Sulfur Compounds: Good resistance to sulfur, hydrogen sulfide, and sulfur dioxide.
Glass Corrosion: Outstanding resistance to molten glass, widely used in glass melting electrodes and stirrers.
Bimetallic Corrosion: Can be safely connected to tungsten, tantalum, and graphite. Avoid direct contact with aluminum, zinc, and copper at high temperatures due to eutectic formation.
Neutron Irradiation: Excellent resistance to radiation damage, retaining mechanical properties under neutron flux.

Manufacturing Standards – Molybdenum Nuts

All molybdenum nuts are manufactured and tested to meet the following standards:

ASTM B386ASTM B387ISO 4032DIN 934ASME B18.2.2JIS B 1181ISO 4033ISO 4034ISO 4161NAS1802MS21042AMS 7847EN 10204 3.1/3.2

We offer surface finishes: black (as-machined), chemical cleaned, ground, polished, and passivated. Special coatings (MoSi₂, Al₂O₃, Y₂O₃) available for oxidation protection. Full traceability and destructive/non‑destructive testing available (UT, PMI, MPI). ISO 13485 certified for medical applications with cleanroom packaging available. Batch cleanroom packaging available for orders containing multiple items of the same size.

Why RAYCHIN LIMITED – The Molybdenum Nut Authority

Refractory metal expertise: Decades of experience with molybdenum, TZM, and MoLa alloys. We ensure precise processing: stress relieving, recrystallization annealing, and surface finishing per ASTM B386/B387 standards. In‑house PMI verifies chemistry of every heat. Our molybdenum nuts achieve full traceability and certified properties.

Global certifications: ISO 9001, AS9100D, ISO 13485 (medical), PED, API Q1, NADCAP accredited processes. All nuts supplied with EN 10204 3.1/3.2 certifications, material test reports, and NACE compliance when required.

Precision tapping & thread forming: CNC tapping and thread forming ensure accurate thread pitch diameter and class fit per ASME, ISO, and DIN standards. Class 2B/6H thread fit. 100% inspection available. Special tooling for molybdenum's unique machining characteristics (brittle behavior at room temperature).

Custom solutions: Special thread sizes, non‑standard heights, proprietary locking features, and tailored packaging. In-house metallurgical laboratory and failure analysis capabilities. Prototype to production volumes supported. Cleanroom wash and packaging available for semiconductor and medical applications.

Contact the molybdenum nut experts

Request a quotation for molybdenum hex nuts, lock nuts, jam nuts, flange nuts, coupling nuts – any standard (ASME B18.2.2, ISO 4032, DIN 934) – any grade (Pure Mo, TZM, MoLa) – any condition (stress relieved, recrystallized), any quantity. Global delivery. Mechanical data in MPa/ksi available for all products.

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