Liquid-solid kneading forming process of zinc-based bearing alloy

Home>Bearing knowledge>Liquid-solid kneading process for zinc-based bearing alloys
/*728*90 created on 2018/5/16*/ var cpro_id = "u3440131";

Liquid-solid kneading forming process of zinc-based bearing alloy

Source: China Bearing Network Time: 2013-08-28

/*250*250 was created on 2017/12/25*/ var cpro_id = 'u3171089';
Abstract: The liquid-solid kneading process of zinc-based bearing alloys was studied. The mechanical functions of the profiles prepared by this process are higher than those of the as-cast ones; this will promote the application of zinc-based alloy materials.
Zinc-based wear-resistant alloy as bearing data; its function can be compared with tin bronze which is widely used in China; it is an aspirational material that can replace tin bronze [1]. China's copper and tin resources are lacking; zinc reserves are abundant; Bearing alloy can handle the problem of domestic bearing materials. However, most of the current zinc-based alloys are supplied by alloy ingots; usually users have limited dosage; most of them have no remelting and pouring equipment; this method is prevented from being used. Combined process; liquid-solid kneading of smelted zinc-based alloy to make different specification profiles and blanks that can be directly machined by users; promoting the application of zinc-based alloy materials.
1 Experimental conditions and methods 1. The chemical composition of the zinc-based alloy used in the experiment is the 3#, 4# zinc-based alloy developed by Luoyang Institute of Technology.
1.2 Smelting and kneading equipment The alloy smelting equipment is a high-frequency electric furnace; the kneading equipment is a YASS-315 type hydraulic press. Firstly, it is smelted and cast into a zinc-based alloy ingot in a high-frequency electric furnace; then the alloy ingot is placed at the hydraulic press site. After remelting in the resistance furnace; liquid-solid kneading; making the blank; the final blank is kneaded by hot solid to form the pipe. Considering the melting of the electric furnace and the stroke of the hydraulic press; the outer diameter of the kneading pipe is taken 50mm, inner diameter of 20mm, length of 400 ~ 500mm.
1.3 Process plan and process road are separated from gravity casting (metal type) and liquid-solid kneading; zinc, aluminum, copper ingot and other alloys are used as materials; alloy ingot melting temperature is 520 ~ 540 ° C. - when solid kneading; preheat the mold to above 100 ° C; pour the molten metal into the cavity; then knead. The main process road is as follows:
Alloy melting (520 ~ 540 ° C) →
Liquid-solid kneading hole type blank (480~500°C)→
Hot solid kneading pipe (280 ~ 300 ° C).
1. 4 liquid-solid kneading mold This mold adopts separate movable mandrel. Before pouring liquid metal, the mandrel is pierced into the concave mold; the lower top rod 2 is topped in the upper limit by the top of the press; To support the mandrel 1. When the kneading is performed, the hollow punch is descended. The mandrel is introduced into the middle hole of the punch; after the molten metal is completely closed, the opening is kneaded. After the liquid metal is poured into the cavity with a lower temperature; Some of the touches on the outside of the mold are quickly condensed; then a thin, closed solid shell is formed. To ensure that the liquid metal crystallizes, condenses and deforms under three-way compressive stress; the back pressure of the ejector cylinder is pre-adjusted After kneading, use the ejector cylinder to push the completely condensed hollow metal blank together with the mandrel to the die; finally, the mandrel is pressed out of the blank outside the mold.
Liquid-solid kneading mold 1, movable mandrel, 2, lower ejector rod, 3-hollow punch, 4-die 2 mechanical function comparison test from the liquid-solid kneading blank of 4# zinc-based alloy; The hot-solid kneaded pipe and the gravity-cast casting are intercepted; the mechanical function is tested. The tensile and impact specimens of the standard shape and scale are prepared as required. The impact specimen is a V-notch specimen; The outer dimensions are 55mm × 10 mm × 10 mm; the V-notch depth is 2 mm × 45 °; each sample takes 3 samples.
Table 2 The mechanical functions of the molded specimens under different process conditions of zinc-based alloy profiles can be seen from the test results; compared with the as-cast zinc-based alloys; the mechanical properties of the zinc-based alloys after liquid-solid kneading deformation are all There is a different degree of progress; the plasticity and resistance goals are multiplied during the period; the solid kneading alloy has the best function; it is more ambitious than the as-cast function. This is mainly due to the kneading deformation of the alloy melt during the crystallization process; Grain refinement of the alloy; and segregation of the composition to obtain 捺. The alloy is kneaded in liquid-solid state; more or less remains of some as-cast arrangements; but when subjected to more intense plastic deformation in hot solid kneading; The as-cast arrangement will be completely eliminated; the alloy arrangement will be more detailed. These can also be reflected in the difference in mechanical function.
3 Wear test Generally speaking; the arrangement of kneading deformed alloy tubing is fibrous; there is a significant flow line; the mechanical function in different directions is not the same; the anisotropy of the arrangement of hot solid kneading tubing is more To be obvious. To clarify the connection between the zinc-based alloy arrangement and the wear-resisting function; the wear test was carried out on the zinc-based alloy under different processing conditions; the experiment was carried out on the MM-200 wear test machine.
The experimental load is 50kg; the speed is 0. 32m/s; the 20# engine oil is used as the lubricant; the conflict time is 2h; the 45 steel shaft sample with HRC50~52 is used as the counter grinding data; the experimental results are shown in Fig. 2.
In addition, the relative wear resistance (ε) of 3#, 4# zinc-based alloy and tin bronze ZQSn6-6-3 was also determined; the experimental equipment and experimental conditions were the same as those of the zinc-based alloy wear test; 1. 5h; the experimental results are shown in Figure 3.
Relative wear resistance ε=B′/B. where: B is the wear scar width of the reference sample (3#) (relative wear resistance is 1). B′ is the wear scar width of the experimental sample.
It can be seen from Fig. 2 that the wear-resisting functions of the liquid-solid and solid kneaded zinc-based alloys are much better than those of the as-cast state; the wear-resisting function of the solid kneading is the best. It can be seen from Fig. 3; The wear-resisting functions of liquid-solid and solid kneaded zinc-based alloys are better than the commonly used bronze data ZQSn6-6-3.
4 The liquid-solid kneading process of zinc-based alloy pipe is completely feasible; the functions of the pipe are significantly better than the as-cast. The tensile strength σb is improved by 20.6%; the elongation δ5 is improved by 4. 7 times; impact resistance AkV improved by 2. 9 times.
Recommend to friends comments close window

Bearing related knowledge
How to carry out the cylindrical bearing bearing device ceramic bearing clarification
Analysis of the Causes of FAG Bearing Oscillation
Analysis of the sliding (smooth) bearing of the NTN bearing device cooperation and preparation work before the adjustment (1)


This article links to http://
Please indicate the bearing network http://

Previous:The ball screw industry said the next series: "What should I do if the FAG bearing is damaged?"

Nylon and Steel Gear Rack

Nylon And Steel Gear Rack ,Powder Coated D Latch For Gate ,Steel D Latch For Swing Gate ,Industrial Door Roller

Jiaxing Gates Hardware Products Co.,Ltd , https://www.jxgateshardware.com