CN105728654A - Process for eliminating microporosity of surfaces of aluminum alloy castings - Google Patents

Abstract

The invention relates to a process for eliminating the microporosity of the surfaces of ZL2xx series of aluminum alloy castings. Because the ZL2xx series of aluminum alloy castings are produced under the normal investment casting technological conditions, the microporosity of the surfaces of the castings is serious, and the castings do not meet the aviation standard requirements and cannot pass fluorescent inspection. In order to control the microporosity of the surfaces of the ZL2xx series of aluminum alloy castings, eliminate the microporosity of the surfaces of the castings and meet the aviation standard requirements, the scattered pouring, cold shell pouring and forced cooling processes are adopted. Accordingly, the microporosity of the surfaces of the castings is eliminated, the requirements for application of the ZL2xx series of aluminum alloy castings are met, and a new approach is provided for controlling the microporosity of the surfaces of the ZL2xx series of aluminum alloy castings.

Description

A kind of process solving aluminium alloy castings surface microporosity

Technical field

The invention belongs to technique processing method technical field, particularly relate to the process of a kind of ZL2 ×× series alloys cast(ing) surface microporosity.

Background technology

Foundry goods microporosity is defined as on related data: the small hole formed between crystal grain in metal liquid solidification process.Being formed of microporosity is mainly relevant with the crystallization range of alloy and casting section thickness etc..The crystallization range of usual alloy is more wide, more easily forms mushy freezing, and last remaining part metals liquid is divided into numerous zonules by solid phase dendrite branch, produces small hole when causing molten metal crystallization between crystal grain.Aluminium alloy castings specifies have sand mould casting method and investment casting method to prepare in air standard, but the ZL2 ×× series alloys foundry goods that investment casting method produces is due to cast(ing) surface microporosity, foundry goods can not pass through to cause that foundry goods learies is big in fluoroscopy, especially more prominent more than showing on 10mm foundry goods at casting section thickness.

Summary of the invention

The technical problem to be solved is: provides and produces ZL2 ×× series alloys foundry goods under full form casting process, and cast(ing) surface, without microporosity, meets the foundry goods that air standard requires.

The technical scheme is that due to ZL2 ×× series alloys foundry goods, produce when normal full form casting process, cast(ing) surface microporosity is serious, does not meet air standard requirement, and fluoroscopy can not be passed through.Loosen to control ZL2 ×× series alloys cast(ing) surface so that cast(ing) surface, without microporosity, meets air standard requirement, take dispersion cast, the cast of cold shell, Constraint Cooling Technology, reach to eliminate the purpose of surface microporosity.Specifically include following steps:

The first step, dispersion cast: when pouring cast part, as much as possible arrange ingate, to reach dispersed metal liquid, reduces the heat local assault to formwork, eliminates the purpose of foundry goods hot-spot；

Second step, cold shell is poured into a mould, and is down to room temperature, pours into a mould after formwork roasting；

3rd, force cooling, after casting pouring, at once foundry goods thickness large part dried or blow CO₂Gas, to reach the purpose of quickly cooling.

The invention has the beneficial effects as follows: by adopting full form casting process to produce ZL2 ×× series alloys foundry goods, it is met air standard requirement, surface is without the foundry goods of microporosity, and all reach requirement through multiple batches of checking, meet ZL2 ×× series alloys foundry goods instructions for use, control surface microporosity for ZL2 ×× series alloys foundry goods and provide a new approach.

Detailed description of the invention:

Below by instantiation, the present invention is described in further detail:

Certain housing design requires to be ZL201 Melt casting, and castings desire fluoroscopy, cast(ing) surface must not have microporosity.So have employed the dispersion of present invention cast, the cast of cold shell, Constraint Cooling Technology method produces.

Disperse ingate when casting moulding system designs, with dispersed metal liquid, made formwork is down to room temperature after 1020 DEG C of roastings, insulation > 1.5h to be cast；Melting ZL201 metal in 100Kg resistance furnace, comes out of the stove in 720 DEG C after molten metal fusing, refine, slag hitting totally, pours into foundry goods；Adopt rapidly compression air that foundry goods thickness large part is carried out pressure after cast and be cooled to less than 300 DEG C, continue to naturally cool to room temperature, shelling cleaning.In 49 foundry goods prepared through above-mentioned process, through fluoroscopy, it is satisfied by user's design, instructions for use.The successful implementation of this process program, provides new thinking and selection approach for solving ZL2 ×× series alloys cast(ing) surface microporosity.

Claims (1)

1. the process solving ZL2 ×× series alloys cast(ing) surface microporosity, it is characterised in that comprise the following steps:

The first step, dispersion cast: when pouring cast part, as much as possible arrange ingate, to reach dispersed metal liquid, reduces the heat local assault to formwork, eliminates the purpose of foundry goods hot-spot；

Second step, cold shell is poured into a mould, and is down to room temperature, pours into a mould after formwork roasting；

3rd, force cooling, after casting pouring, at once foundry goods thickness large part dried or blow CO₂Gas, to reach to be quickly cooled to the purpose of less than 300 degree.