DK150530B - COMPOSITION FOR THE MARKING OF HEATING, INCLUDING GLOSSY GLASSING ARTICLES OF IRON OR STEEL - Google Patents

Description

in 150530

The present invention relates to a composition for labeling heat, preferably glowing articles of iron or steel having a surface temperature above 200 ° 0, consisting of aluminum as the reducing agent for oxides 5 on the surface of the iron or steel article, a pigment and an adhesive, which composition can is applied by spraying on the hot surface.

The conventional way of labeling a hot steel article is to write manually on the surface with a piece of chalk or with a waxy color pen that melts at high temperatures and leaves a permanent marking. However, the labeling of a hot item in this way is unsatisfactory because the person carrying out the labeling has to stay close to the object, whose high temperature and associated health risks can lead to fatigue, inattention and incorrect markings. Since the work is monotonous, the risk of errors is high. If markings are missing, a cast block, block or flake cannot be identified 20 and therefore must be discarded, resulting in significant financial loss. Moreover, the labor cost of such a method is high.

Japanese Patent Specification No. 65.08019 proposes the use of a ceramic material for marking 25 of hot steel, it is proposed to spray the material onto the surface, in particular with the mention of an aqueous solution of ZnSO 1 * (Example 1) and a lick containing sodium silicate , boric acid, anhydrous chromium oxide and 49% water (Example 2). The use of powder is mentioned in passing.

A glazing of the material appears to be intended to produce a glassy layer which, however, will tend to break during subsequent rolling of the steel in a rolling mill. Use of wet materials is also inconvenient since the steam generated by contact with the hot metal removes much of the useful material.

U.S. Patent No. 2,150,530 to U.S. Patent No. 3,296,689 discloses the use of an aluminum paint for metal marking, in particular, it is proposed to apply a paint containing 20% aluminum flakes in a resin paint brush. On-5 spraying is suggested as an alternative. The purpose of the aluminum is to provide a recognizable zone of deviant temperature on the hot steel article.

Pra DE Publication No. 1,669,144 is known to apply a paint which is intended to prevent gas corrosion of metals and containing powdered aluminum and at least one refractory oxide of a divalent metal or a compound which upon heating gives it refractory oxide, preferably in the form of a suspension in a liquid carrier. If a dry powdered product is to be sprayed onto the metal surface, a binder such as phenol formaldehyde resin which is cleaved at higher temperatures is used.

DE-Publication No. 1 669 212 similarly discloses a composition of aluminum powder, pigment 20 and wax to prevent discoloration of iron and steel objects when heated to high temperatures. Here, too, a wax is used which evaporates when the composition is heated to the high temperature.

According to DE patent application No. 1 077 815, a mixture of sodium water glass, aluminum powder and iron oxide red is used for marking steel. To avoid clumping, it is recommended to add water to the mixture applied through a template to steel before glowing.

It is an object of the present invention to provide a hot metal marking material, especially steel, which material reliably adheres and is sufficiently resilient to survive subsequent processing.

It is also an object of the invention to provide a marking material suitable for application in a manner that allows the operator to stay at a sufficient safety distance from the object.

It is a further object of the invention to provide a marking material which can be applied by means of simple equipment that is only slightly exposed to wear and which requires little maintenance.

The materials selected must be as resilient as necessary to the temperature of the surface on which they are to be applied. The lowest active temperature of the adhesive may well exceed 200%; eg. the temperature of the metal can be 1200%.

On iron or steel surfaces, the aluminum powder serves to reduce the primary rolling iron oxides, thereby preventing or reducing subsequent flaking of the underlying rust mark.

It is of particular importance that the material is dry during application. The carrier gas used to spray the material onto the metal surface should preferably also be very dry, and if compressed air is used, it should be preconditioned to a dry and dust-free state.

The requirements that must be set for a marker powder are that it must not be toxic and should not contain predominantly volatile constituents. The requirements that must be placed on the mark produced are that its contrast and visibility must be good when the object is both hot and cold, and further that the mark must not go off during rolling. The label should not contain components that are harmful to the steel; it should be temperature resistant in the event of subsequent thermal finishing and should not disappear during storage and transport in free air.

These requirements are met by a composition of the kind mentioned in the preamble of the invention, characterized in that the composition is a dry powder and can be applied in powder form and that the pigment is TiOa and the adhesive is the binding agent. bentonite, the aluminum being over 50% by weight of the material and having a grain size below 600 µm, while the TiO 2 used has a grain size of at least 3 µm and not more than 5 µm and the bentonite 5 has a grain size less than 75 µm.

The composition of the invention can be used not only for labeling steel in the form of e.g. hot steel blocks, bricks, thick sheets and other sheets, but also with equally good results when marking iron, e.g. hot cast iron molds (molds) and casting plates.

A preferred apparatus for applying the composition of the invention is illustrated in the drawing, the only figure of which shows schematically a conventional spray gun 15 modified for application of the composition and shown mainly in section.

In the drawing, a hot cast steel block 1 to be labeled is shown schematically moving beneath an outflow nozzle 2 on a spray gun 3 to 20 dry materials from which a carrier gas jet 4 which carries dry marking powder onto the hot steel block 1 is shown.

The handgun spray gun 3 is of a conventional design? Examples are Type GB Fluid Sprayer from 25 The DeVillbiss Company, Toledo, Ohio, U.S.A. and Type Ec-co 40 sprayer from Atlas Copco Tools AB. No protection is sought for the syringe as such. The syringe is modified by equipment with a longer outlet tube 5 starting from a mixing vessel 6 for the nozzle 2. A suitable nozzle dimension 30 is 3 mm.

Compressed air, which is conditioned to be dust-free and dry, is supplied through a hose 7 which knows. by means of a nipple 8 is connected to a channel 9 in the handle of the syringe 3f 10. A trigger 11 controls a main control valve 12 located in the channel 9. A needle valve 13 enables the air pressure to be regulated. The pressure in the hose 7 can typically be 6 at and reduce to 0.2-1 by the valve 13.

The handle 10 is secured to a lid 14 for the container 6, and the duct 9 proceeds as a tube 15 into the container 6 with an orifice located outside its axis so that the outflowing air provides a vortex that swirls marker powder 16 in the container upwards. . Thus, the powder is drawn into the air stream 10 which flows through the outlet tube 5 from the lid 14. A very constant concentration of powder in the air jet can thus be obtained. In this embodiment, the length of the outlet pipe 5 is about 2.5 m, so that the operator's hand can be at this distance from the hot metal surface. The nozzle is preferably held for approx. 5 cm from the hot surface.

An example of a marker composition according to the invention is given below.

Example

Component Grain Size Weight Parts T1O2> 3µ; <5h 2

Al <600µ 8 25 Dry bentonite containing 2.5% by weight

Mg <75µ 5

This powder was applied to a steel surface at a temperature of 1200 ° C by the conventional hand-held powder spray gun with an extended discharge tube as shown in the drawing, so that the operator's hand was at least 250 cm from the metal surface. Compressed air was supplied at a pressure of 6 at and reduced to 0.2-1 at before flowing into the container 6 with the powder. Spray gun nozzle