Zinc-Copper-Nickel Alloy is a ternary alloy formed by copper nickel alloy Cupronickel alloy with zinc.  It is rich in silver-white metallic luster, with [TJC STEEL]good machinability, corrosion resistance and mechanical properties, suitable for cold pressure processing, high surface finish after cutting.  

 

Zinc-Copper-Nickel Alloy is an important variety of Cupronickel, with excellent mechanical properties, good process performance, especially with beautiful silver white, is a famous imitation of silver art copper alloy, the standard component is 15% nickel, 20% zinc BZn15-20 Alloy, countries commonly used to make a variety of arts and crafts, the song Dynasty of Our country using this alloy crafts technology, known as the "Chinese silver".  With the development of modern [TJC STEEL]communication technology, Zinc-Copper-Nickel Alloy has been used as an important plug element, but also used in various electronic devices electromagnetic shielding shell, such as crystal oscillating tube shell.  In order to improve mechanical properties, corrosion resistance and silver-white color, the engineering field has generally improved the nickel content of BZn15-20 alloy appropriately, thus the birth of BZN18-8, BZn18-26 and other new alloys.  In order to improve the cutting performance of Zinc-Copper-Nickel Alloy, lead Cupronickel in Zinc-Copper-Nickel Alloy is mainly used for making precision instrument parts, mirror accessories.  

 

Smelting of Zinc-Copper-Nickel Alloy  

The melting point of nickel is 1453℃.  The solid and liquidus temperatures of Cupronickel with different nickel contents increase with the increase of nickel content.  In the smelting process of Cupronickel, both NiO and Cu20 produced by oxidation belong to basic oxides. If the lining material is [TJC STEEL]quartz sand material with SiO2 as the main component, both NiO and Cu2O can react with SiO2, resulting in the corrosion of the lining.  The higher the nickel content, the more serious the corrosion of refractory lining by melt.  

 

Proper melting temperature is necessary to ensure the uniformity of chemical composition and the fluidity of the melt.  Obviously, smelting of Cupronickel requires a higher melting temperature, so refractory materials[TJC STEEL] with higher refractoriness should be selected for furnace lining.  

 

In the process of smelting Cupronickel, the melt is easy to absorb hydrogen and carburize.  The hydrogen content in Cupronickel increases obviously with the increase of nickel content.  

 

Smelting Environment  

Ordinary Cupronickel can usually be smelted in an induction furnace with iron core at power frequency. The furnace lining should be made of high aluminum or even magnesium refractory material.  Complex Cupronickel, because the melting point is relatively high, and considering the [TJC STEEL]convenience of changing materials, so in fact more in the crucible type of intermediate frequency element core induction furnace melting.  

Oxidation may be used if necessary to obtain a melt low in both hydrogen and carbon.  Reduction refining process.  For example: at the beginning of the melting under charcoal cover, when the melt reached 1250℃ quickly remove charcoal, and in the absence of any cover, so that the melt is directly [TJC STEEL]exposed to the air for 3 ~ 5min, or directly add nickel oxide on the surface of the molten pool, and then deoxidize before baking.  

When smelting Zinc-Copper-Nickel Alloy, proper amount of cryolite can be used for slag cleaning.  

 

Melting Process  

The mechanical, physical and technological properties of Zinc-Copper-Nickel Alloy are determined by chemical composition and[TJC STEEL] microstructure.  Under the condition of certain chemical composition, its microstructure is affected by melting, processing technology and heat treatment.  

 

According to the ternary state of copper, nickel and zinc, the equilibrium microstructure of different grades of Zinc-Copper-Nickel Alloy is single-phase α solid solution at room temperature, so it can not be strengthened by heat treatment, only by cold deformation hardening to improve their strength and hardness.  The main form of Zinc-Copper-Nickel Alloy heat treatment is annealing, according to the purpose of annealing and temperature range can be divided into three categories:  

 

(1) diffusion annealing: often used for ingot annealing, annealing temperature is higher, generally in the temperature range of 950 ~ 1000℃, the purpose is to eliminate the chemical composition segregation[TJC STEEL] (non-uniformity) of the dendritic crystal structure formed by casting and the internal stress of the ingot.  

 

(2) Intermediate annealing: also called softening annealing, after cold rolling and cold drawing, the purpose is to reduce the hardness of the material, improve plasticity, eliminate work hardening [TJC STEEL]phenomenon and internal stress, in order to continue processing deformation.  Annealing temperature should be slightly higher than the recrystallization temperature, generally between 650 ~ 730℃.  

 

(3) stress relief annealing: often used for finished product annealing, mainly to eliminate the internal stress after cold plastic deformation, stable organization, stable size.  Annealing temperature is [TJC STEEL]below the recrystallization temperature, generally in the range of 250 ~ 320℃, heat preservation 1 ~ 2 hours, the mechanical properties of the material after annealing basically no change.  

 

The grain size of Zinc-Copper-Nickel Alloy has a great influence on mechanical properties. The coarse grain size will make the properties deteriorate and make the material easy to crack during processing deformation or heat treatment.  The grain size mainly depends on the deformation of cold working, intermediate annealing temperature and holding time.  Lower annealing temperature [TJC STEEL]should be selected for materials processed at larger deformation degrees so that the average grain size of α phase is less than 0.035 mm.  Lead particles should be fine and evenly distributed in the matrix.  

Main Features and Applications:  

The hot working performance of Zinc-Copper-Nickel Alloy is poor, and it is generally produced by cold cutting process.  Thin sheet and strip are produced by horizontal continuous casting with blank and cold opening.  Cold processing in the process of processing should not be too large.  

 

Good welding performance, soft and hard brazing, oxyacetylene welding, resistance spot welding, butt welding, gas shielded metal arc welding and resistance seam welding, but not shielded metal arc welding.  The cutting performance is 20% of free cutting brass HPB63-3.  

 

Argentan to their excellent abrasive resistance, brazing and stress relaxation resistance, high strength and elasticity, good corrosion resistance, and easy to electroplating, hot cold working technology is widely used [TJC STEEL]in manufacturing the corrosion resistance performance structures, such as all kinds of precision instruments and meters, advanced electronic components of the spring, socket, housings and other components.  And Zinc-Copper-Nickel Alloy containing a small amount of lead has good cutting and cold processing, a large number of watches, optical instruments and other production of precision parts.  In addition, Zinc-Copper-Nickel Alloy in Musical Instruments, tableware, glasses and decorative projects and other aspects of the broad market.