CN105238978A

CN105238978A - Preparation method of high-strength magnesium alloy profile

Info

Publication number: CN105238978A
Application number: CN201510626598.XA
Authority: CN
Inventors: 穆锦辉; 吴稀勇; 崔妍; 李江海; 陈利红
Original assignee: TIANJIN DONGYI MAGNESIUM PRODUCTS CO Ltd
Current assignee: TIANJIN DONGYI MAGNESIUM PRODUCTS CO Ltd
Priority date: 2015-09-28
Filing date: 2015-09-28
Publication date: 2016-01-13

Abstract

The invention provides a preparation method of a high-strength magnesium alloy profile. The magnesium alloy profile prepared through the method comprises Al, Zn, Mn, other impurities of Fe, Ni, Cu and Si with the content of 0.05%, and Mg serving as a matrix. According to the preparation process route, a blank is prepared through the components, the blank is subjected to homogenization, extrusion and profile aging heat treatment, homogenization temperature ranges from 350 DEG C to 420 DEG C, and time ranges from 10 hours to 24 hours; the extrusion ratio of the extruded profile is larger than 30; the heat treatment temperature ranges from 170 DEG C to 230 DEG C, and time ranges from 6 hours to 30 hours. According to the performance of the profile, the hardness reaches HW 11-12 or above, and the bending performance can reach 80%-90% that of a commonly-used 6063-T5 aluminum alloy profile. The preparation method has the beneficial effects that the homogenization treatment process is adopted at the early stage of the method, the structure of the blank is optimized, casting blank defects are eliminated, and follow-up profile extrusion is facilitated. By the adoption of the proper aging treatment process, the final property of the profile is improved, the extrusion speed of the profile can be increased by about 10%, and meanwhile the service life of a mold can be prolonged to a certain degree; through aging heat treatment, the hardness can be increased by HW 1-2.

Description

High-strength magnesium alloy section bar preparation method

Technical field

The present invention relates to a kind of high-strength magnesium alloy section bar preparation method.

Background technology

Magnesium alloy is as the lightest practical metallic substance, it has high specific tenacity and specific rigidity, good diamagnetism, high electronegativity and thermal conductivity, good antidetonation damping capaicty and excellent machinability, easy recycling, in addition aboundresources, oneself becomes the preferred material in the fields such as automobile, 3C industry, aircraft industry.Along with the expansion of magnesium alloy Application Areas, the research and development of magnesium alloy also enters the New Times.The mechanical property of pure magnesium is poor, often directly do not use as structured material, but pass through the integrated use of the multiple methods such as strain-hardening, grain refining, alloying, heat treatment reinforcement, magnesium base compound or these methods, the mechanical property of magnesium is significantly improved.The alloying of magnesium is the most basic in reality, the most frequently used and the most effectively strengthens approach in these methods, and the selection of alloying element and thermal treatment process are the keys of strengthening.So by adding a certain amount of trace element and obtain uniform composition, fine microstructures by thermal treatment process in alloy, excellent performance and the good magnesium alloy of comprehensive mechanical property become the important research direction of field of magnesium alloy.On composition describes, general magnesium alloy composition only indicates different-alloy element or foreign matter content in describing, and magnesium does not need to illustrate as matrix again.

In order to improve the intensity of magnesium alloy profiles, all to add a large amount of rare earth elements and to obtain high-strength magnesium alloy section bar by complicated technique in the selection of alloying element.Rare earth element is not only expensive, and than great, prepare high-strength heat-resistant magnesium alloy significantly improve causing the cost of alloy by interpolation high rare-earth content.In the extruding of conventional magnesium alloy profiles, general direct employing D.C.casting blank, extruding after blank stove or main frequency furnace heating, loose owing to existing in D.C.casting process, shrinkage cavity, the defects such as segregation, can cause the difference of product forms Microstructure and properties, thus reduce lumber recovery in thin-wall section extruding.

Conventional extrusion magnesium alloy system is AZ series, general multiplex AZ31.Compare with aluminium alloy, magnesium alloy profiles product tensile strength is high, but compressive strength is low, is not suitable for environments for use such as bearing bending, compression.As AZ31 tensile yield strength can arrive 160MPa, but compression yield strength 90MPa, far below 6063-T5 aluminium alloy.

Summary of the invention

For deficiency structural in prior art, the object of this invention is to provide a kind of high-strength magnesium alloy product forms preparation method, first homogenizing heat treatment is adopted, improve blank tissue, eliminate the ununiformity structures such as segregation, be solid-solubilized in the second-phase of separating out in cast simultaneously, reduce the breakthrough pressure in extruding, to improve extrusion speed and die life.Owing to adopting suitable composition range, after can extruding, carry out aging strengthening model, to improve section bar performance further.

For achieving the above object, the technical solution used in the present invention is to provide a kind of high-strength magnesium alloy section bar preparation method, magnesium alloy profiles composition prepared by the method comprises: Al:4.5 ~ 6.6%, Zn:0.5 ~ 1.5%, Mn:0.2 ~ 1.5%, other impurity Fs e, Ni, the content of Cu, Si is 0.05%, Mg is matrix.

Preparation were established: obtain blank by mentioned component, carries out homogenizing-blank extruding-section bar aging strengthening model by blank, described homogenization temperature at 350 ~ 420 degree, 10 ~ 24 hours time; The extrusion ratio of extruded section is more than 30; Thermal treatment temp 170 ~ 230 degree, 6 ~ 30 hours time.

Described section bar performance: hardness reaches HW11 ~ 12 or more, bending property reaches 80 ~ 90% of conventional 6063-T5 aluminium alloy extrusions.

Effect of the present invention is that the method adopts Homogenization Treatments technique early stage, optimizes blank structure, eliminates casting blank defect, be conducive to follow-up profile extrusion.Adopt suitable aging treatment process simultaneously, improve the final performance of section bar.Through Homogenization Treatments, profile extrusion speed about 10% can be improved, also can improve die life to a certain extent simultaneously; Through aging strengthening model, hardness HW1 ~ 2 can be improved.

Embodiment

High-strength magnesium alloy product forms preparation method of the present invention is illustrated in conjunction with the embodiments.

High-strength magnesium alloy product forms preparation method of the present invention is based on conventional AZ series alloy system, and to magnesium alloy chemical composition, extrusion process parameters, heat treating regime is optimized, to improve magnesium-alloy material compression or bending property.By optimized alloy composition, adjustment extrusion process and heat treatment parameter, make Properties of Magnesium Alloy reach Aluminium Alloys in Common Use performance.As lighting material, can be used for general structure part product forms, reduce energy consumption etc.Homogenization Treatments uses on aluminum alloy high-performance profile extrusion, but in magnesium alloy profiles extruding, what use at present is little; In high-strength magnesium alloy product forms preparation method of the present invention, be optimized for the blank of different-alloy composition and homogenization process, finally can realize the magnesium alloy profiles product close to aluminium alloy 6063-T5 performance.

The magnesium alloy profiles composition of of the present invention kind of high-strength magnesium alloy section bar preparation method comprises: Al:4.5 ~ 6.6%, Zn:0.5 ~ 1.5%, Mn:0.2 ~ 1.5%, other impurity Fs e, and the content of Ni, Cu, Si is 0.05%, Mg is matrix.

Embodiment is to prepare magnesium alloy circular tube

(1) first prepare blank: alloying constituent is Al:5.5%, Zn:0.8%, Mn:0.4%, other impurity 0.05%, Mg are matrix; Specification Φ 92 × 350mm, Homogenization Treatments temperature 400,20 hours time.

Then, on 500 tons of extrusion machines, Φ 25 × 1.2mm pipe is squeezed into.Extrusion billet temperature 360 ~ 380 degree, extrusion stem speed 1.2 ~ 1.4mm/s.Thermal treatment temp: 200 degree, 20 hours time.

Final pipe hardness reaches HW12, and bending property reaches 90% of same specification 6063-T5 aluminium alloy.

(2) first prepare blank: alloying constituent is Al:5.0%, Zn:1.0%, Mn:1.2%, other impurity 0.05%, Mg are matrix; Specification Φ 76 × 350mm, Homogenization Treatments temperature 380,24 hours time.

Then, on 630 tons of extrusion machines, Φ 25 × 1.0mm pipe is squeezed into.Extrusion billet temperature 360 ~ 400 degree, extrusion stem speed 1.0 ~ 1.5mm/s.Thermal treatment temp: 180 degree, 20 hours time.

Claims

1. a high-strength magnesium alloy section bar preparation method, magnesium alloy profiles composition prepared by the method comprises: Al:4.5 ~ 6.6%, Zn:0.5 ~ 1.5%, Mn:0.2 ~ 1.5%, other impurity Fs e, and the content of Ni, Cu, Si is 0.05%, Mg is matrix;

Preparation were established: obtain blank by mentioned component, carries out homogenizing-blank extruding-section bar aging strengthening model by blank, described homogenization temperature at 350 ~ 420 degree, 10 ~ 24 hours time; The extrusion ratio of extruded section is more than 30; Thermal treatment temp 170 ~ 230 degree, 6 ~ 30 hours time;