Test material substrate selection model: commonly used in recent years quality chromium steel

(2) paint:

1 precoating primer: selection of magnet epoxy ester antirust paint.Because after the pretreatment of steel on the set of welding steel structure, need after welding and cutting, grinding and other processes, the paint layer surface is inevitably there are a lot of defects such as scratches and fall off, so the selection of current locomotive steel structure commonly used high temperature, heating influence is small, anti-corrosion properties of strong magnets epoxy ester antirust paint the precoating primer for steel surfaces.

2 primer: phosphoric acid polyurethane primer.Steel structure welding after forming, in order to repair its surface defects, but also for the next step of putty or coated with paint to prepare, general need for steel structure and then spray 1 times primer.The primer and next process with putty and overcoatability.Verified by the production of zinc phosphate primer, polyurethane can completely meet the requirements.

4.2 test procedure

The 4.2.1 sample surface treatment model will be divided into A, B two group, the 12 block, wherein the group A by sandblasting treatment, group B sandblasted, with only 240# emery cloth polishing.With organic solvent two groups of sample surface clean, cold wind blowing, placed in a dryer.

The preparation of A film 4.2.2 model, B model of the group take 6, spraying 1 zinc phosphate primer for polyurethane, drying; and A, B group and the other 6 examples, sprayed with 1 magnets epoxy ester antirust paint, drying the 48h, and then spraying 1 zinc phosphate primer for polyurethane, drying.

Performance test of 4.2.3 (1) on the preparation of good film group A, group B model, respectively, thickness measurement, then do the following properties: 1 test: the adhesion tester, according to GB/T1720.2: salt water performance test by 3%NaCl solution, according to GB/T1763 test.(2) 2 primer will spray test plate process matching test.

(1) adhesion.

After coating plate corrosion resistance depends on the adhesion of coating adhesion size, bigger, stronger capability of sheet metal corrosion.Table 1 shows: film thickness, sandblasted samples than unmodified sandblasting thick; adhesion, sandblasted samples not less than without blasting processing model.

(2) of resistance to salt water.

Brine resistance refers to the model in salt, at the required temperature for immersion, observe the erosion degree.Salt water resistance is a measure of the film as well as material anticorrosion ability is an important index.Table 1: as can be seen by shot blasting and spraying paint, spraying precoating primer model than the uncoated precoating primer template anticorrosion ability; the same spray 2 primer, sandblasted model anti-corrosion ability than without blasting strong.

(3) process matching.

Paint process matching means two paint on together, between the layers is "at the end of the bite", shedding, blistering, wrinkling phenomenon.Don't appear these phenomena, that support good.Can be seen: whether sandblasting model or without blasting processing model, different paint magnet epoxy ester antirust paint with zinc phosphate polyurethane primer process matching good, no bubble, "at the end of the bite" phenomenon.This shows that: after sandblasting, sprayed magnet epoxy ester antirust paint as a pretreatment of steel, welding into the steel structure is then coated with a layer of zinc phosphate polyurethane primer.

5 conclusion through the test, and ultimately determine the steel structure new surface treatment and coating technology, namely by sandblasting and precoating primer combination of surface treatment process of steel: first is sandblasted, increasing the roughness, and then spraying the 1 magnet epoxy ester antirust paint as a precoating primer, to prevent steel after blasting corrosion of steel structure, welding after forming, the last 1 of zinc phosphate coating polyurethane primer.The process from the beginning of 1999, has been successfully applied to Sri Lanka EMUs and several other models, without any quality problems, indicates that the process is in full compliance with the design requirements and processes, to achieve the desired results.(end)