How to make a brilliant stainless steel kettle?
Today, you can not afraid to admit that objects from stainless steel firmly and confidently entered the daily life of mankind. We regularly encounter them - this street fences, and various elements of the interior design in the business center, just prefer stainless steel specialists, architects and design in the construction of business premises and shops. The list is endless.
But there is a stainless steel that we use every day in the home - it's all sorts of dishes. Knives, forks, pots, bowls made of stainless steel have won recognition for its versatility, environmental friendliness, attractive appearance and processing characteristics. This cookware is easy to care, suitable for almost any occasion - from a family dinner to a business meeting or a gala evening. A special place in this series takes stainless steel kettle. It is almost always filled with water, which requires a material of improved physical characteristics and the resistance to fluid. Because even stainless steel may be subjected to oxidation (corrosion) under the influence of external sources.
Experts 'Kipo Systems' many years working with the subject stainless steel in all its manifestations, during which time we have gained extensive and valuable experience in the processing of the material from the negative manifestations of any kind. We have the desire (not an exaggeration even say - the need) to share their knowledge with those who care about this subject matter - and experts, who are daily engaged in stainless steel, and ordinary users, for whom the most valuable practical advice. Therefore, we created fro articles. They "Kipo Systems" will try to tell you how long to retain the steel in its original condition, which technologies are used for the treatment of stainless steel, which cover there are a lot of anything else.
How to make a brilliant stainless steel kettle?
1.Grinding and polishing of stainless steel abrasives.
2.Classification of the stainless steel surface.
3.Electropolishing and chemical polishing of stainless steel.
4.Pros and cons of abrasives and chemical polishing.
5.How to get rid of the discoloration during the heating of stainless steel. Using an etching paste.
6.Preparation of the workplace for processing stainless steel.
7.Selection of equipment for grinding and polishing stainless steel.
8.The coating of titanium nitride ("golden"): the pros and cons.
9.Working with stainless steel, titanium nitride coated.
10.What brand are better used in corrosive environments and on the street.
1. Grinding and polishing of stainless steel abrasives.
Our first topic that we will address concerns the processing of stainless steel using abrasives. Grinding and polishing of stainless steel can not only achieve excellent surface appearance, but also give the material the protective properties for which he is so much appreciated.
Tell us how to polish the surface with a stainless abrasive?
The essence of grinding - the removal of ultrafine layer from the metal surface, which allows to eliminate existing irregularities. Grinding is used as the primary treatment, and for the elimination of defects with ready-made products. One common way is to use abrasive grinding - special materials of natural or synthetic origin. In the process of mechanical polishing abrasives is important to choose the right size of the grain. For qualitative processing process is repeated several times while each time following a grain diameter of the abrasive tape decreases. Features and configuration items do not always allow them to use automated processing (flat or round grinding machines), so often done by hand sanding belts or sponges. It is important not to forget to clean the surface of the material by abrasive particles. This is done by means of water, at the same time allowing the product to cool.
How to make a beautiful surface of stainless steel and shiny?
Experts' Kipo Systems "recommended treatment by polishing. For this purpose, ultra-precise abrasives with minimum grain size (roughness). This allows for a special shine and smoothness. But it is important to remember that in the process of grinding and polishing abrasives Steel loses oxide film from the surface, which gives it the properties of stainless steel. It is therefore important for a few hours after treatment, when the surface is most susceptible to external influences, treat it with protective means to prevent the appearance of defects. In addition, special attention when grinding and polishing abrasives should be given welds - because of their vulnerability, need to use special materials (ceramics, zirconium).
The final polishing includes processing using special polishing wheels of fabric materials (eg felt), and the use of polishing paste, which gives a special shine and luster of the surface (because we want our Maker shone and pleased with its appearance, is not it right?). But this will be discussed in a future materials.
2. Classification of surfaces of stainless steel.
Industries modern society has reached such a level of development that allows for the processing of stainless steel in different ways and have a unique output surface. The most widely used standard grinding, mirror surface (including "supermirror"), textured, colored ("golden"). Today we will try to find out what they are and what type is best suited for our favorite teapot.
Conventional grinding is divided depending on the acceptable level of surface roughness for that have entered a special notation. Levels range grinding comprises several meanings: matte, slightly roughened, gloss, etc., which are designated 2R, 2G, etc. Type of grinding is largely dependent on the used abrasive (120 grit, 240 grit, etc.).
Another surface that is most prevalent in the food and construction areas, a mirror processing. It can be divided into three main categories: the matte surface of the mirror, reflecting and so-called "supermirror", which is characteristic of a particular level of treatment, which has found application in the elegant and expensive interior. To obtain a smooth surface from stainless steel, the experts' Kipo Systems "conducted a vertical annealing followed by polishing to perfection. At the output, in addition to a beautiful appearance, we have higher barrier properties and a long life of such products.
An interesting treatment option is the production of stainless steel with embossed textured surfaces. Such materials can have dozens of different patterns - "grain", "under the skin", and they are felt by touch, ie have relief. There grooved surface which prevents slipping, which is important in the manufacture of floor coverings (its thickness is usually 3-5 mm). Surely you have seen coverage of stainless steel, which has the effect of drizzle - as if you are on a cold day. This option is popular in the interiors of business and office centers. Also, stainless steel with embossed decoration can be seen in some of the new metro station in St. Petersburg - as a ride on the new branch and look to cover the escalators.
Finally, the most luxurious and stately way to the surface treatment of stainless steel - spraying "in gold." Produced such decoration using titanium compounds (nitride). As you might guess, the most widely used she received in the interiors and exterior of the building - for example, this option is used in the manufacture of domes for temples, which can significantly save costs. In addition to the "gold" surface treatment electrochemical method allows you to get dozens of different shades to suit every taste and imagination of the designer. Titanium nitride - a very strong external influences to the connection, so the service life of such products is almost endless.
3. Electropolishing and chemical polishing of stainless steel. And how is polished stainless steel, except the abrasive?
When the task is a particularly smooth surface, processing specialists often use techniques such as chemical and electrolytic polishing. What is their essence? Chemical polishing is that the item is made of stainless steel or sheet is immersed in a container with a special solution, which reacts with the metal. As a result, the metal is subjected to dissolution, all disappear from the surface roughness due to their higher activity in comparison with a smooth surface. Since this process is accompanied by the release of an active gas, it is recommended to move the material in the container to the gas bubbles formed do not interfere with the chemical polishing.
There is also a variant of this method - electrochemical polishing. It is characterized in that the process is not only a special solution and electric current. Detail of the stainless steel acts as the anode, the cathode is a copper electrode. Stainless steel is used for polishing solution consisting of phosphoric acid and sulfuric acid with the addition of glycerin, water and anhydride. The maximum time for which the item is immersed in such a solution is 30 minutes. One of the advantages of electrochemical polishing is a great shine and smoothness of the surface by the formation of her thin oxide film.
Now let's imagine that our Maker for the operation of some faded, scratched, and we need to polish it from the outside. In this case, it is most expedient to resort to the method of electropolishing. Compared with the conventional mechanical method, it has several advantages:
- Process several times spent less time (4-5 times)
- Does not require much physical effort
- It allows you to give greater surface shine
Therefore, if we want to get up in the morning and look out the our Maker instead of a mirror - choose electropolished. It is carried out using polishing wheels straight profile connected to the universal electrical machine can also be used drilling machine, which is fixed polishing disk of felt or cloth.
4. Pros and cons of abrasives and chemical polishing.
Today we will try to find out what are the advantages and disadvantages of different ways of processing stainless steel. As for treatment with abrasives, all the drawbacks are obvious. Firstly, this process is rather long and laborious. During processing one should not change the abrasive belt, to result in a material with excellent appearance and physical characteristics. This is caused by the requirement to reduce the grain size of the abrasive and to the wear, from which during processing due to friction flies grains. In the process it is necessary to permanently remove the garbage start up and cool the surface, the material does not lose its valuable properties. Add that not every detail of the complex configuration can be handled automatically. We have to do everything by hand, which takes a lot of time and physical strength. Advantages treatment using abrasives - possible to give an excellent appearance of the product (using particularly fine grains) relatively low cost (especially when not using the machine, and carry out the processing manually - consumes only abrasive material and human power), simplicity of technology, in comparison with chemical polishing.
What, in this case, advantages the chemical polishing?
Specialists in stainless steel "Kipo Systems" is used in the various methods, so we were able to evaluate the pros and cons of all of them. Relatively simple chemical polishing. Its main advantage - the best properties of the treated surface in terms of gloss and smoothness (especially in electrochemical polishing). Furthermore, the polishing by means of chemical compositions is much faster time and requires great physical effort.
But this advantage smoothly into one of the disadvantages of this method. Because of the need to constantly maintain a fixed composition of the solution (otherwise there is a risk to spoil metal) chemical polishing requires careful monitoring throughout the process. In addition, the solution used quite dangerous to human health, which requires increased caution.
5. How to get rid of the discoloration during the heating of stainless steel, the use of the etching pastes.
Any processing of stainless steel, are associated with increased temperatures may lead to the manifestation of this effect as annealing. It is the formation of very thin oxide film on the surface of the material, which as a result starts to "play" with different colors - straw, brown, purple, blue. Once the formation of spots of different colors is an indicator of the required heating temperature. Incidentally, this phenomenon apparently looks quite beautiful, and in some areas of production (such as weapons) is often especially so given the task to process steel, that its surface has a certain color. But more still this effect is undesirable, so try to figure out how to deal with tarnish the processing of stainless steel.
If relate solely to the use of stainless steel household (tableware), there is the effect of tarnishing get pretty hard, as it manifests itself at high temperatures. The same maker can overheat and start playing with flowers, but it will not tarnish, but a simple optical effect - rainbow coloring. But in industrial production, this problem is very urgent. The higher the heating temperature, the more stable becomes colored spots (as the oxide layer thickens). To remove tarnish from the surface of stainless steel, it is possible to resort to machined polymeric brushes with abrasive. But it's best to use special means for etching - pastes, gels, sprays. These tools allow you to restore the properties of stainless steel (passivated it, returning the protective film) and return the original color. They consist mainly of acid - nitric, sulfuric, hydrofluoric, and persistent fluoride compounds. It is important to avoid over-pickling, which can degrade the corrosion resistance of steel.
Technologically, the process of using the etching pastes can be divided into several stages:
- Clean the surface from dirt and rust with a special composition.
- Directly etching. The paste or spray applied over the entire surface of the material is soaked for half an hour to one and a half hours (depending on the degree of damage and ambient temperature), then rinsed with water.
- For best properties of stainless steel specialists' Kipo Systems "recommends then treat the surface with a passivating composition.
This will form a homogeneous protective film that returns become its property. Passivation can pass and just in the air, but this process is a long one, moreover, there is a risk of non-uniform film formation.
6.Workplace preparation for processing stainless steel
At this time, we would like to touch on such an important issue as the preparation of the workplace in the processing of stainless steel. We enjoyed our favorite tea every day for several years, it's time to "patch up" - to return the original luster and remove fine scratches on the surface. For this purpose it is necessary to re-polish maker.
If someone does not know - all the processes associated with the processing of metals (including stainless steel), are regulated by special instruments and standards, developed a number of specifications and guests. This allows you to observe safety at work, as well as to maintain quality at the proper level. First, in the processing of stainless steel is necessary to use only certified materials, which is labeled the manufacturer. All automatic devices (grinding machines, etc.) Should be checked for serviceability, special importance is given to the question of reliability of fastening moving parts - nozzles, circles, disks, heads. When the need to ensure adequate protection of eyes, breathing with the help of special glasses and masks. The fact is that some chemical compounds (e.g., when the chemical polishing electrolytes) are extremely dangerous for human beings. In case of contact with their skin or eyes possible serious injury.
Directly workplace should be detached and arranged so that when the treatment is not going contacts between high-alloy steel and ordinary carbon - this may lead to a decrease in the quality of the first because of the loss of its properties. In this regard, "Kipo Systems" advises to use only special abrasives intended for stainless steel. The fact that this material is more complicated grinding and polishing than ordinary steel, and thus the requirements for abrasion will be higher. The best would be to use abrasives with polymer and ceramic compounds - they do not cause overheating of the surface.
Another important point in the grinding and polishing of steel - a properly fitted grinders and abrasive belts. This allows not only to reduce the processing time, but also to avoid unwanted damage to the surface of the metal (in case of too large grains or made wrong chemical composition). Experts " Kipo Systems ", based on his experience, it is recommended to gradually reduce the size of the abrasive grains, gradually reaching to the value of 400 grit. This must be replaced at least three dimensions. This will provide a smooth and glossy surface.
7. Which equipment do you recommend to use when grinding and polishing of stainless steel?
In our address frequent requests for advice and tell the right equipment for the processing of stainless steel. The right choice of equipment and materials - the key to successful treatment of stainless steel. Needless to say that all the equipment must be checked regularly and to work - It is a truism. But due to the high requirements for the processing of stainless steel, there are a number of specific points that must be remembered.
Firstly, because of the content of alloy elements is not recommended to treat stainless steel on the same hardware, which previously worked with a conventional steel or aluminum. This can lead to poor anti-corrosion properties of the material. If there is no alternative, then you need to carry out thorough cleaning of all parts and mechanisms of metal residues.
Second, the initial step includes a rough, rough grinding steel from visible to the naked eye defects in the weld and others. She made a grinding machine, it is important not to overdo it with the number of revolutions - overheating harmful to stainless steel.
Third, after the initial processing has been done, we move on to more thorough. It is important to closely monitor the state of abrasives. Too fine grain can not provide the required level of grinding is too large may lead to new scratches and damage to the surface, and the work will have to do again. It is also necessary to monitor the state of the abrasive belts and brushes - WHEN SEWING grains should make change. Every decrease in the grain size of the surface is cleaned of dust and residues with water and wipe with a cloth.
Fourth, after a hard abrasive surface treatment, it is advisable to go to a polishing wheel out of felt, felt, petal brushes. This will allow "clean finish" stainless steel. It also is important to monitor the temperature of the metal and do not overheat.
Finally, in the processing of stainless steel can not do without special greases and polishing pastes. Such aids at the final stage of the surface to give a special shine. Optimal use of pastes based on chromium oxide. Besides the visual attractiveness, pastes serve to recreate the metal protective film (passivation), which is lost in the process of rough processing.
8. The coating of titanium nitride (golden): pros and cons.
I'm sure many of you have seen the building, whose facade or interior elements were covered with metal that looks like real gold. Knowing the price of the precious metal, it is not difficult to understand that to use it would be too costly. For such cases, and there is a coating of titanium nitride.
The essence of this method consists in the following: on the stainless steel sheet at high temperature or by vacuum plasma spraying (there are other methods - the condensation of the ion bombardment, gas-phase deposition, etc.) is applied to a thin layer of compounds of titanium with nitrogen. Depending on the ratio of these two elements, it is possible to obtain a variety of colors - gold, copper, bronze, and others. The most common demand is titanium nitride coating is "golden." It is used for manufacturing of advertising designs, finishes and entertainment centers, restaurants and casinos in dentistry. Remember the fashion for gold teeth? So, not all there is real gold - much cheaper to install it more affordable substitute. In addition, this coating is overdue in the construction of temples (the dome is much cheaper to cover the "gold" of stainless steel than with gold leaf) and electronics (chip parts).
What are the basic requirements for the steel with titanium nitride coating it? In fact, everything is simple. The main condition - the steel must be a minimum thickness of 0.5 mm. Type of polishing is not so important - it may be a matt material, textured or mirror. Remarkably, with stainless steel cover "under the gold" is changing not only the appearance of the product, but also its physical characteristics. It is established (and experts' Kipo Systems "can confirm this) that the film of titanium nitride attached to stainless steel high resistance to the negative impact of any rainfall (so it is relevant to use in the finishing of the exterior of the building). Furthermore, such a stainless steel without problems undergoes further processing - cutting, stamping, polishing, bending. A coating of titanium nitride is excellent in adhesion to metal, which ensures a long life - 50 years or more. The "gold" will not fade, do not fade and will not lose its color. Another great feature - increased resistance of stainless steel to scratches, chips, and other troubles. Finally, such a covering is environmentally safe - both in operation and in manufacture.
Do you have coverage "under the gold" shortcomings, you ask?
To some extent disadvantage is shades such coatings that an experienced chemist or a materials Unlike real gold even without a special analysis. For the rest, it all depends on where the "grow hand" at the Masters and how they comply with the technology. It can only be coated onto the prepared and specially treated steel.
9. How to work with stainless steel, titanium nitride coated?
When installing different decorative designs, specialists "Kipo Systems" periodically ask the question:
How to serve the objects coated with titanium nitride? Are there any features?
What can you say about this?
As it is known, one of the advantages of the coating (in addition to aesthetic properties) - this improved performance compared with conventional stainless steel. She's well behaved at home, and coated with titanium nitride these qualities still increasing. And corrosion is higher and longer lasting gloss. It is no coincidence, for items made of stainless steel, manufactured using sodium nitride, give a guarantee of 50 years. But it is important to remember important detail: in no case do not skimp on quality steel! The content of alloying elements must be at a sufficient level (for example, the percentage of chromium - not less than 18), otherwise there is a risk that the adhesion of sodium nitride film to become a bad and eventually begins to flake coating. The best option is a brand of steel AISI 304. No less important is the process of applying the composition of the base material, temperature, layer thickness, uniformity, etc.
If you're still unable to protect our "golden" tea and it appeared scratches or rust - do not despair, it's possible to correct! It is only important to follow some simple rules. If you need to be polished - because of the small thickness of the coating it should be done with caution, you can not do with the tapes or brushes abrasives. We recommend the use of soft felt or of felt heads, special polishing pastes, which correspond with the titanium nitride coated. These pastes will help remove small scratches and rust (it may occur if working with stainless steel using the wrong tool) contain passivation and polymer components. As a result, the problem is resolved, and the product will regain its original luster.
10. What brand are better used in harsh environments or outdoors.
Today we will try to illuminate this question: how to choose the right steel for use in hostile environments? Stainless produce a lot of different products - from utensils to piping and components of various mechanisms in heavy industry (up to the aerospace industry). Accordingly, the requirements to be met by steel will be different.
As for the work in corrosive environments (such as exposure to strong acids, salts, pairs), here the principle of material selection is based on several key parameters. Firstly, the content of major alloying elements - chromium. This figure should be equal to 17 or more, but in this case, we can confidently say that stainless steel will conduct themselves properly in hostile environments. Second, the additive elements. These include nickel, niobium, titanium, cobalt and others. Adding some of these elements (or several) in the recipe allows steel to give it one or another useful property. For example, titanium and niobium prevents intergranular corrosion.
Choosing stainless steel for use in corrosive environments, the first thing to pay attention to the ferritic steel, as well as composite material - austenitic-ferritic and austenitic-martensitic steels. These types of steels are well established when working with solutions of salts and acids (nitric, hydrochloric, sulfuric, phosphoric, hydrofluoric and others, solutions of ammonia), as well as in chemical, food and energy. In a special category can be identified chromium-nickel alloys (such brands as 06HN28MT, 14X17H2, 09H15N8YU, 08X17H5M3, 03H16N15MZB). Depending on the percentage of the main alloying elements and additives, such stainless steel allow to work even in boiling sulfuric or phosphoric acid, concentrated nitric acid, which is especially important for welded structures. Steel 06HN28MDT able to operate even in radioactive environments that have been applied in the chemical industry.
Such marks as 04X18H10, 08H18N10 (AISI 304), 03X18H12, intended for the manufacture of the mechanisms operating at elevated temperature in the nitric acid.
There steels (eg, grade austenitic steel 08H17N13M2T), which are intended for use in aggressive environments and at high temperature (up to 600o C). Mark 10X17H13M2T (or otherwise AISI 316Ti) also is designed for a long service life due to forming part of molybdenum and titanium. This brand is excellent for the shipbuilding industry, chemical, pulp and paper production.
By the way, there is no direct relationship between a successful operation of a particular grade of steel in an aggressive environment and its resistance to high temperatures or physical exertion. The steel may behave in a hydrochloric acid or medium, but to collapse under the mechanical action. This factor must be considered when choosing the optimal grade of steel. Therefore, for use in the streets it is recommended to use some other steels.
AISI 201 austenitic steel comprising in its composition from 14 to 16 percent chromium, additionally alloyed with nickel, manganese, copper. Brand has a high corrosion, is used in the food and consumer industries, in the construction of guardrails in buildings, fences Stainless steel bins.
The excellent corrosion resistance, in the manufacture of outdoor constructions may be employed in AISI 316 and AISI 316Ti. Ferritic steel AISI 430 has higher strength properties, due to the low-carbon structure is practically not subject to corrosion (subject to manufacturing technology, as experts' Kipo Systems "is not mentioned once, and then touch the still).
If the task is to choose the best, in terms of the ratio of strength / Anti-corrosion steel type, we can recommend the widespread grade AISI 304 (the Russian equivalent 08H18N10). This steel is characterized by a low percentage of carbon in the composition is not affected by precipitation (including acid rain terrible big cities). Above 18% chromium composition provides reliable protection film (passivation layer), which opposes the negative influences. These properties have made in AISI 304 almost indispensable in the manufacture of tanks for food, utensils, medical devices, architecture, construction and decoration.