51results about How to "Narrow melting range" patented technology

The invention discloses a halogen-free flame-retardant EVA (ethylene vinyl-acetate) composite material which comprises ethylene vinyl-acetate and a composite flame retardant in a mass ratio of 3:2. The composite flame retardant is prepared from ammonium polyphosphate, tri(1-oxo-1-phospha-2,6,7-trioxa bicycle[2,2,2]octane-4-methylene) phosphate and a fatty amine substituted phosphonitrile derivative, wherein the mass ratio of ammonium polyphosphate and tri(1-oxo-1-phospha-2,6,7-trioxa bicycle[2,2,2]octane-4-methylene) phosphate is 2:1, and the mass ratio of the fatty amine substituted phosphonitrile derivative and the mixture of ammonium polyphosphate and tri(1-oxo-1-phospha-2,6,7-trioxa bicycle[2,2,2] octane-4-methylene) phosphate is (1-15):(25-39). The composite material disclosed by the invention has good comprehensive flame retardance and mechanical properties. In the processing and preparing process, the compatibility and processibility of the composite flame retardant and EVA are good and the composite material can be widely applied as cable raw materials and the like.

The invention discloses a quenching solder for connecting hard alloy and steel as well as a preparation method and a connecting method of same. The quenching solder comprises the following components in percentage by weight: 28-33 percent of Ag, 18-20 percent of Zn, 1-8 percent of Ni, 5-9.5 percent of Mn, 3-6.5 percent of Co and 1-3 percent of Sn, and the balance of Cu. The preparation method of the quenching solder comprises the following steps: preparing the raw materials with the proportion into master alloy by adopting an electric arc melting method, continuously jetting a master alloy melt to the surface of a rotational cooling copper roller by using high-pressure argon to form a foil strip. A method for connecting the hard alloy and the steel by adopting the material comprises the following steps: carrying out surface treatment on the quenching solder, the hard alloy and the steel and then putting into a vacuum furnace by using a special fixture for brazing. The quenching solder has the advantages of low melting temperature, narrow melting interval, uniform solder melting and strong diffusivity of alloy elements; and through the connecting method, parts are wholly heated, the thermal stress is small, and the deformation can be controlled to a minimum limit, therefore, a stable and reliable joint can be obtained, and good joint strength is obtained.

The invention relates to a method for preparing a pellet by pre-treating high titanium type vanadium-titanium magnetite. The method comprises the following steps of carrying out fine ball milling pretreatment on the high titanium type vanadium-titanium magnetite by using an ore milling device, so as to enable the proportion of the particle size, which is less than 75 microns, of magnetite powder to be greater than 85 to 95 percent; drying, so as to enable the moisture of the high titanium type vanadium-titanium magnetite powder to be less than or equal to 1.3 percent; dry-mixing the dried magnetite powder and bentonite for 15min to 20min, and subsequently, spraying water, and wet-mixing for 15min to 20min; putting a wet-mixed raw material in a condition of 25 to 30 DEG C, braising the material for 25min to 35min, then putting into a pelletizer, and preparing a green pellet with a diameter of 10mm to 12.5mm; drying the green pellet; afterwards, roasting, and raising the temperature of the pellet to 800 to 900 DEG C according to a temperature rise rate of 10 to 12 DEG C per minute; afterwards, raising the temperature to 1,140 to 1,180 DEG C according to a temperature rise rate of 4 to 6 DEG C per minute, and roasting for 10min to 15min; subsequently, lowering the temperature according to a temperature fall rate of 5 to 8 DEG C per minute, taking out after the temperature is fallen to 300 DEG C, and carrying out air cooling. The method provided by the invention can be used for effectively improving the pelletizing performance and the pelletizing speed of the high titanium type vanadium-titanium magnetite, is used for enabling the strength of the green pellet to be best, moreover, is lower in roasting temperature and shorter in time, can be used for meeting the requirement of the compression strength of a mature pellet, and is used for obviously improving the production efficiency of the pellet of the high titanium type vanadium-titanium magnetite.

A moderate temperature copper-based solder and a preparation method thereof relate to a solder and a preparation method thereof. According to the moderate temperature copper-based solder and the preparation method thereof, the technical problems that the current copper-based solder has great brittleness, cannot be processed into solder wires nor brazed with steel and stainless steel, and is more likely to generate poisonous zinc vapour are solved. The moderate temperature copper-based solder is prepared from Cu, Zn, Mn, Si, Sn, Ni, La and Ce. The method comprises the following steps of: 1, weighing materials, 2, preparing rare earth intermediate alloy; 3, smelting moderate temperature copper-based solder to obtain metal ingot; and 4, extruding the metal ingot to obtain the moderate temperature copper-based solder. The moderate temperature copper-based solder does not contain silver, Ga, In and other noble metal elements, so the preparation cost is low. The moderate temperature copper-based solder does not contain any poisonous elements, is safe and reliable to use and has high brazing mechanical property; and at room temperature, the moderate temperature copper-based solder can be applied to the brazing of steel, stainless steel and other black metals due to high mechanical property.