#WHAT IS METAL BLASTING/PEENING?
Metal oxidates and corrodes over time. Metal blasting/peening is a method that applied by a proper blasting machine for remove lubricant, soil, filth, dirt, rust and corrosion on the metal. Prepares the metal to be paint. Paint process prolongs metal’s life.
Blasting procedure is applied by special production abrasive by name grit. Metal blasting both removes rust and corrosion which are visible or in micronized dimensions on the metal and reveals extract of the metal.
A metal blasted freshly is unguarded to rust and corrosion. After metal blasting procedure if the metal leaves humid envoriment it is seen that it is oxidized in a few hours and oxidation manifests itself with change of color. Therefore blasted metal has to be protected as soon as possible, has to be painted and contact with air of metal has to be prevented. The best application is zinc painted.
Aim of blasting procedure is to clean the metal that will be painted properly by proper machine firstly and create pores and roughness. In this way, pint can hold on to metal surface. Blasting procedure provide roughness as in sand paper. It is imposible that applied paint can’t stick on the metal surface by any chemical reaction. For absolute sticking surface has to be roughened by proper abrasives.
WHAT IS THE DIFFERENCE BETWEEN SHOT BLASTING AND SANDBLASTING?
The main difference is that in the shot blasting process we use throwing wheel and in sand blasting process compressed air is used.
Shot blasting: Abrasive gets accelaration through the throwing wheel, which is rapidly turning in a special steel housing, with one side oriented opening. Shot blasting is used for blasting metal, different profiles and welded constructions.
Sand blasting: Abrasive is dosed into the stream of compressed air and gets a real acceleration in the outflow from the blasting nozzle. Sandblasting is used in the blasting rooms, blast cabinets, pressurized portable sandblasting machines, vacuumed sandblasting machines.
ABRSIVES USED IN BLASTING MACHINES
For blasting machines various blasting abrasives are used. These abrasives can be metal base, glass and mineral base. It is very important that to choose right abrasive. For all sorts of blasting machines, types of abrasives that will be used are different. Stainless steel ball, glass bead, aluminium oxide ball, steel grits, basalt, silica, quartz are used as abrasive.
Silica: There is quite thin types of silica. Generally, silica is used for thin sheet metal in order to light blasting.
Basalt: Dust emmision of basat is low and this abrasive is used at indoors and it is used in the place where the abrasive can be rcyled.
Grit: Dust emmission of grit is low and power of blasting of grit is the best. Actually, it is not sand it is iron wastes.
SURFACE CLEANING VALUES
Surface cleaning values are evauated according to ISO 8501-1:1998 ve TSE EN ISO 8501-1 standarts.
According to ISO 8501-1 surface cleaning values as follows.
Sa 1 < 80% Light cleaned
Sa 2 80% Well cleaned
Sa 2.5 96% Very well cleaned
Sa 3 99% Complete cleaned
WHAT IS SANDBLASTING/SHOT BLASTING MACHINE, HOW IT WORKS?
Blasting is a surface treatment method that is based on blasting or throw the particles (abrasive) on the workpiece surface at high speed by sandblasting/shot blasting machine. This process known as scraping at ship building industry, shot or shot cleaning (peening) at other many industries and this process is used for different purposes from various metals to glass, from beton to fabric and from steel ball to granulated glass, from silica sand to apricot seed many different abrasive materials are used. Shortly, sandblasting/shotblasting machine can be described thus; sandblasting/shot blasting machine is the machine that provides to throw the particles (abrasive materials) that are used for blasting to the preferred surface at high speed. Many sandblasting/shot blasting machines contain additional equipments and workpiece carrying systems along abrasive blasting process. Additional equipments make prepared the flung particles (abrasive materials) which are collected and cleaned due to be thrown again (recylng). Workpiece carrying systems provide the hitting of the abrasive to the workpiece in proper angle and proper speed. There are 2 key features while sandblasting/shot blasting machine is designing.