Oddly enough, but on high-quality, good stainless steel, rust may appear over time. This occurs, as a rule, in the so-called "aggressive environment", with high humidity and temperature. To prevent this from happening, do not allow the contact of steel with dust and metal shavings.
Welding stainless steel.
During subsequent processing, do not expose the product to the harmful and destructive effects of alkali and acids. After welding, a thin oxide layer is formed on the surface of the product. It weakens the resistance of the compound to corrosion. Corrosion is divided into electrochemical and chemical.
- Electrochemical - is the collapse of the metal in electrolytes.
- Chemical - is the destruction of metal from exposure to the environment.
Methods for processing stainless steel after welding
To do this, you need a special protective suit and mask. As a rule, sulfuric, hydrochloric, hydrofluoric or nitric acids in the form of gels, pastes, aerosols, and sprays are used in etching. For pickling seams, it is better to use pasta with a very thick texture. Paste must be applied with a brush, a very even layer.
The first method is acid etching.
- Scaling with hydrochloric and sulfuric acid. It is necessary to observe the strictest control of the saturation of the solution and temperature.
- Rinse with water.
- Immersion in a bath with a mixture of hydrofluoric and nitric acid.
- Thorough rinsing.
The process of pickling stainless steel acids.
Vapors of acids are formed in the air; this requires a serious approach to the protection of the skin and respiratory organs. This process has many different variations with the concentration of the composition, time and sequence of actions.
Electrolytic etching is one of the methods of acid etching. An electric current, either direct or alternating, is passed into the bath; it has a mechanical effect. The above methods are very complex and require large financial investments.
The second method is etching with ready-made mixtures of acids after welding.
- First, remove all traces of dirt, rust, and grease stains. The composition is applied for half an hour.
- Final treatment with passivator.
This is an easily accessible cleaning method. As for precautions, the paste should not be heated, exposed to direct sunlight. There must be good ventilation in the room, these compounds have a pungent, unpleasant smell. If paste comes into contact with skin, immediately rinse with water.Back to table of contents
Mechanical methods and heat treatment after welding
Minimal processing is the removal of slag and scale by grinding the seam with a stainless steel brush. In some cases, this is not enough, and additional chemical treatment is necessary. Grinding with fine-grained sandpaper is very common.
Etching products from stainless steel with acid.
Mechanical methods are sandblasting, liquid abrasive and water sandblasting. A prerequisite - the minimum content of iron in the sand. After this cleaning, the surface is passaged.
Heat treatment of stainless steel is divided into several types: quenching (maximum temperature and rapid cooling), annealing (metal heating and slow cooling), normalization (similar to annealing, the difference is that cooling occurs in fresh air, but not in a furnace), tempering ( held after quenching).
From the correct heating of the workpiece depends on the final result and the quality of the product. Under the influence of heat metal changes its structure and properties. When overheated, it acquires an undesirable coarse-grained structure. Monitor the heating temperature must be very carefully. For example, burnout is a marriage that is no longer subject to correction.
Chemical-heat treatment of stainless steel - heat treatment with the application of various elements on the surface (chromium, aluminum, nitrogen, etc.)Back to table of contents
Features of passivation of stainless steel
This method of cleaning will help eliminate all contamination from the metal surface, as well as create the necessary corrosion resistance, contribute to improving the appearance of the product, and keep it from possible contamination in the future. Passivation is a protective film that forms on the metal surface and reliably protects it from damage and destruction. The passivator should be applied for half an hour, and it is possible on a wet surface.
The method of spraying means evenly distributed over the entire surface.
After the required time is maintained, the passivator is removed from the product. For this, as a rule, a water compressor is used.Back to table of contents
In order for the product after welding to acquire a finished look, the welds must be machined with a grinding machine.
After welding, you need to bring the product into a proper, finished look, give it shine, gloss and shine. Thanks to the use of new technologies in polishing, the time spent on this work has been significantly reduced, and the quality has increased.
Polishing is the use of a special grinding machine. Mode, you must choose the one that is recommended by the manufacturer. Features polished pipes are that they have impeccable appearance, are durable and durable. Polishing can be manual, ultrasonic and machine. At home, ordinary sandpaper, abrasive grinding materials, files may be suitable.
The first step is to get rid of the rough seam, to make the surface smooth and uniform. To complete this task you will need a development circle. He will easily remove the rough seam, remove scale. Now the surface is prepared for further action.
The second step is to remove risks from the first processing. The surface is brought to a state close to the final. Sometimes at this stage you can stop. The surface is already looking good.
The third step is the final polishing. Bringing metal to a mirror shine. At the same time, when polishing a stainless steel, microscopic defects are removed from the surface, and when polished - coarse ones.Back to table of contents
Grinding: practical recommendations
Classification of welds by position in space.
When doing this work, do not forget to prepare well. Wear a mask to avoid dust in your eyes. Polished products are subject to clearly visible defects: scuffs, scratches and so on. You will need grinding heads that have abrasive belts.
To obtain the desired result, the steel is polished in several passes. Remember that the right materials and tools will allow you to reduce work time and improve its quality, this is a guarantee of excellent results.
Grinding of finished products is performed using abrasive sandpaper. This material has a paper or fabric base with a coating of very different grains. Wet sanding is done with waterproof skins. Coatings can be made of glass as well as silicon. Grinding is the final stage of the process of processing stainless steel after welding. It evenly removes all top layers.
Materials you will need:
- grinding wheels with different grit;
- wood glue;
- polishing paste.
For grinding of welds on stainless steel products you need a grinder.
The first thing you need to remove the influx of metal from the weld. You can do this grinder. If the surface is sufficiently smooth and even, you can immediately proceed to the second stage. Prepare a felt circle, using ordinary trowel, apply carpenter glue to the surface of the workpiece. Carefully and carefully walk on the abrasive crumb, which can be obtained from the emery cloth.
Then sand the surface three or four times. The size of the abrasive should be reduced. The surface of the stainless steel must be washed after each grinding.
It should be perfect, absolutely smooth and even, without rough edges. Otherwise, you have to redo everything again. In the next step, you will need a felt disc and polishing paste. It is better to find a diamond, with a degree of grain that matches your metal. This is a finish polish that removes visible risks. You will see how the surface transforms and becomes smoother.Back to table of contents
A few words in conclusion
So, the pros have become known for a long time. Material "stainless steel" tightly entered the life of every person. He has a place almost everywhere, even in a modern kitchen, many items are made of high-quality stainless steel. Such popularity is due to the good characteristics and properties of this wonderful metal.
After proper processing, it looks perfectly beautiful, in its mirror surface you can see your own reflection. This material is one of the most durable, strong and durable. The stability of this material is simply amazing. But in order for everything to be this way, you will have to tinker a bit.
Processing steel after welding is a rather laborious, complex and laborious task. It requires real skill, professionalism and absolute accuracy of performance. It will be difficult for a novice home master to master this intricate science, but with the right and responsible approach, the result of work will undoubtedly please you.
Most importantly, do not forget about the danger that you may encounter when performing such work, it is very important to observe all precautions. And then come the necessary experience, skills and dexterity.