Heat Treatment Process | Annealing, Sintering, Brazing & Hardening

Solution

Heat treatment shapes metal mechanical performance. Many factories face temperature instability, oxidation and high energy costs. Rexin offers custom furnaces for annealing, quenching, sintering and vacuum brazing. Precise atmosphere & temperature control ensures consistent quality for global metal processing manufacturers.

What is Heat Treatment?

Heat treatment is metallurgical processing that modifies metal internal grain structure via controlled heating, holding and cooling cycles to achieve target mechanical properties. All standard thermal cycles contain 3 mandatory core steps:

Heating Stage: Heat workpiece to preset temperature to activate grain recrystallization
Soaking Stage: Maintain constant temperature for full uniform microstructure transformation
Cooling Stage: Cool by oil, water, air or vacuum; different cooling rates form distinct metal structures Temperature interval and cooling method are two decisive factors of final workpiece quality.

Common Heat Treatment Processes

English Process	Process Function	Typical Workpiece Application
Annealing	Slow furnace cooling to eliminate internal stress & soften metal for stamping/machining	Stainless strip, tube, raw forgings
Normalizing	High temp heating + air cooling to refine grain & boost tensile strength	Carbon steel structural parts
Quenching	Rapid cooling to form high-hardness martensite	Gears, shafts, cutting tools
Tempering	Low-temperature reheating after quenching to reduce brittleness & balance toughness	Bolts, molds, dies
Carburizing	Carbon permeation on workpiece surface for surface hardening	Low-carbon steel fasteners, small gears
Nitriding	Nitrogen infiltration to gain high surface hardness without quenching	Precision molds, auto engine parts
Solution Treatment	High temp heating + fast cooling for anti-corrosion performance	201/314/304/316/410/420 stainless steel, aluminum alloy
Brazing	Metal bonding under protective atmosphere without base metal melting	Heat exchangers, refrigeration hardware

Matching Industrial Furnace Types

Furnace Model	Best Application Scenarios	Core Advantages
Box Resistance Furnace	Small batch molds, tools, trial production	Low investment, flexible batch processing
Vacuum Furnace	High-precision zero-oxidation treatment for tools & molds	No decarburization, mirror bright surface, tiny deformation
Mesh Belt Continuous Line	Mass automatic fastener & metal strip production	24h non-stop operation, uniform temperature, energy saving
Atmosphere Controlled Furnace	Bright annealing & copper brazing	Adjustable nitrogen-hydrogen protective gas
Pit Nitriding Furnace	Long shafts, large mold nitriding treatment	Large loading capacity, low operation cost

High Energy Consumption

Long-time high-temperature operation leads to huge electricity & gas cost

Strict Environmental Rules

Waste gas & quenching fume treatment required by local environmental laws

Shortage of Senior Process Engineers

Experienced thermal technicians are hard to recruit globally

Unstandardized Process Parameters

Different factories adopt inconsistent craft standards, unstable product quality

Metal Microstructure & Performance

Three mainstream metal microstructures formed by different heat treatment:

Martensite: Ultra high hardness, high brittleness (produced by quenching for cutting tools)
Bainite: Balanced high strength & toughness (produced by austempering for auto gears)
Pearlite: Moderate hardness, good machinability (produced by annealing/normalizing for raw metal blanks) Accurate temperature control enables precise adjustment of metal internal structure to meet different production requirements.

Popular Advanced Heat Treatment Technologies

Vacuum Heat Treatment: Zero oxidation & decarburization, ideal for high-end molds, bearings and cutting tools
Low-pressure Carburizing & Plasma Nitriding: Improve surface hardness without sacrificing base metal toughness
Intelligent PLC+HMI Digital Control: Real-time temperature/atmosphere monitoring, remote access, automatic production data recording

Industry Development Trends

Development Direction	Description
Intelligent Manufacturing	AI automatic parameter optimization, unmanned continuous production
Green Energy Saving	Waste heat recovery, low-power insulation, circulating protective gas system
High Precision Vacuum Equipment	Vacuum furnaces gradually replace traditional salt bath & atmosphere furnaces
Global Unified Certification Standards	CE, ISO compliant furnace design for cross-border export

Conclusion

Heat treatment is the core manufacturing process that decides metal product competitiveness. As global manufacturers raise higher requirements on workpiece precision, surface quality and energy conservation, thermal processing equipment will develop toward intelligence, energy saving and high precision.

Rexin Machinery supplies full-series custom furnaces matching all above heat treatment crafts, supporting factory wholesale, non-standard customization and full turnkey production lines. Contact our engineering team to get tailored technical proposal and formal quotation.

Our Products: Mesh Belt Furnace, Vacuum Furnace, Box Furnace, Pit Nitriding Furnace, Brazing Line, Sintering Furnace

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