DE2908575C2 - Use of steel components made from a non-magnetic steel - Google Patents

Description

The invention relates to the use of steel components made of non-magnetic steel material, the one Electrically insulating cover, preferably made of one synthetic resin, for embedding in concrete, mortar or cement compounds. Such a steel material cannot rust, and this causes an increase in magnetic permeability in steel even after a long time Avoided service life, and it is still fully electrically isolated

In the present application, for the sake of simplicity, the term "concrete" is used in the following, which, however, also includes casting mortar and cement should include.

A non-magnetic steel material is a steel material that does not work in an external magnetic field is magnetized. A non-magnetic material that called a material with a low magnetic permeability, is often used as a building material for steel frames or steel posts or rods used in concrete structures and under a strong, external magnetic field, such as B. in experimental nuclear reactor devices or experimental core melting devices or railway foundations for those of the magnetically levitating kind

As a non-magnetic steel, an austenitic stainless steel is already known; an example of this is an 18 Cr-8 Ni steel. Since this steel contains a relatively large amount of Ni, it is relatively expensive and it has It is therefore generally used as a material for steel frames or steel bars for the Reinforcement in concrete unsuitable

A non-magnetic steel of the high Mn series is described in US Pat. No. 4,090,025. He however, it does not contain a large amount of Ni and is cheaper than the above-mentioned Cr - Ni series austenitic steel. It is stable to plastic work and heat, maintains its low magnetic permeability, and it is therefore believed that it can be used in many ways for the uses listed above. A Such steel meets when it becomes a steel rod or like processed by hot rolling, the criteria of magnetic permeability μα 1.02, which is usually considered the standard specification of a non-magnetic steel. For use as general non-magnetic steel its effect is therefore sufficient.

In structures, however, where the slightest magnetic Variation must be avoided, as in geomagnetic observation test fixtures or in structures where there is a strong alternating magnetic field occurs, as in experimental nuclear fusion devices, the steel material used in these structures should not only have a low magnetic permeability but it should also be in its properties before installation as well as during the Be stable in the structure during use. The following difficulties prevent the above conditions from not being satisfied by the usual non-magnetic steel materials.

il) Rust is formed on the surface of non-magnetic steel, causing an increase in the magnetic permeability of the steel occurs

(2) Heat is generated by induced current flow through the steel material, particularly in the case of steel rods that are incorporated into concrete.

The difficulty caused by rust is that The rust formed even on non-magnetic steel material contains iron oxide as a base. The most effective magnetic permeability μ of the steel material with rust formed is given by the following formula shown:

μ = 1+ (1-Q *, + Cx ₂

where x represents the magnetization of the steel material, x _{2 represents} the magnetization of the grate, and C represents the production rate of the grate (a weight ratio of the rust formed to the weight of the steel material).

For non-magnetic steel, x \ is very small (<0.01) but as large as about 10 compared to X _2. Therefore, even if the formation of rust is little and C is small, the apparent value of μ is large for the entire steel material . Therefore, when these materials are used in a structure where a little variation in magnetism is a problem as mentioned above, an undesirable influence is generated. However, the influence of rust in the non-magnetic steel material has not yet been investigated the storage and transport of the steel material or during the handling of the material in the work area. There is also a great possibility that rust will be formed if the material has been stored in concrete for an extended period of time. As mentioned above, the slightest production of rust causes great trouble in a special material such as non-magnetic steel.

The influence of the induced current in the steel material will be explained below because it is non-magnetic Steel material becomes an electrical conductor when it forms an electrical circuit and a magnetic one Field is given, an induced current is generated when non-magnetic steel materials embedded in concrete are isolated from one another, i.e. H. If you are not in direct contact with each other, no difficulties arise. It is difficult to find one, indeed To use a series of steel bars or the like within a structure that are in non-contact with each other. the Formation of an electrically closed circuit can be in a structure made of steel rods or the like, which are in concrete embedded, cannot be avoided. When a

such a structure exists in a strong magnetic field created by the use of high currents, such as in electric refiner for aluminum, is formed, or when it is in a strong magnetic field, such as in a nuclear fusion device, the induced current that is formed in the steel rods will be so large that the structure is easily destroyed due to the expansion of the steel material and the heat embrittlement of the concrete by generating heat.

It is an object of the present invention to provide a non-magnetic steel material in which such difficulties inherent in non-magnetic steel materials as above mentioned, kept to a minimum or avoided.

The applicant has found that to eliminate the above-mentioned problem (1) a protective coating non-magical steel can be applied, the does not give effective magnetic permeability of the non-manganese steel and which is effective in formation prevents rust on the surface of the steel To eliminate the difficulty (2) a vlektrisch insulating cover attached to the non-magnetic steel. It is preferable to use a non-magnetic To apply coating that has both rust protection and electrically insulating properties

In the drawings is

F i g. 1 is a plan view of part of a grating from FIG non-magnetic rods using the surface-coated non-magnetic rod of the present invention Stahls and

Fig. 2 is an oblique view for determining the electrical resistance of a concrete slab that has the Steel bar lattice from F i g. 1 includes

In the present invention, suitable coatings that prevent rusting are metal coatings, such as Zn, Al or Sn, a coating that is an inorganic compound as a base material, such as a Phosphate, or oxalate, contains, coatings of organic Ranks, as in synthetic resin, or rust preventive, as in oil or grease, or a By-product of the petroleum refinery. The metal coating must if a metal coating for the steel material is used, consist of a non-magnetic metal.

Methods of coating include a method in which a non-magnetic steel material is in molten metal is immersed, an electroplating process or an Al or similar melt spray or Alitier- or, Kalorisierverfahren. Such coating processes can be carried out in the same stage used as be; general steel materials. Before coating the non-magnetic steel however, it is essential that the steel be well descaled

A coating for electrical insulation is explained below. As indicated above, the electrically insulating coating used to hold steel rods or the like, which are incorporated into concrete structures, electrically isolate even if they touch each other. This upper pull can therefore only be applied to the parts that are believed to touch each other. However, if that coated Steel material is manufactured in a factory before installation, it is more practical to use the total surface area of the steel to coat.

Of course, the coating material was mixed have a high electrical insulating property. The above-mentioned metal anti-rust coatings, such as from AI or Zn, cannot be used as insulating coatings. In contrast to the anti-rust coating is the close contact with the non-magnetic steel material does not pose such a problem, and therefore one can use a method of coating in which, for example, a tubular or tubular Rubber or synthetic resin is adapted to the exterior of the steel material.

ίο Materials such as • Rubber or rubber, cotton cloth, hemp cloth, jute paper, as it is or impregnated with Grease, tar, or any synthetic resin can be used. Such insulating coatings can be on

is the entire surface of the steel material after one common coating methods, or they can be applied to just part of the steel are applied, so that a contact of the steel materials with each other by so-called. Spacers during of use is avoided.

The anti-rust or insulating bed was above described. However, some coating materials provide the function of both of these coatings. For example, a synthetic resin coating has excellent properties both as an anti-rust property like aucii as an insulating material, it is comparatively easy to apply and gives the coating layer a high strength in the case of handling the coated steel material.

Suitable synthetic resins for the coating material include vinyl chloride resin, epoxy resin or Polyolefin resins such as B. polyethylene or polypropylene. Appropriate coating methods for these materials are powder spraying method, thermosetting method, a painting method using a liquid resin or a melt extrusion coating process.

The composition of the non-magnetic steel to be coated is not particularly limited Da precisely the non-magnetic steel material that has the coating layer according to the invention for The uses to be used as mentioned above can be non-magnetic steel containing the Belongs to series with high Mn content, is cheap and the has the most practical mechanical and other properties.

Sumitomo Metal Industries, Ltd. is the assignee of Japanese Patent Laid-Open No. 1,50721/77, which on December 14, 1977. The one in it

steel so described, d. H. a steel containing 0.2 to 14% C, 5 contains up to 30% Mn and 0.1 to 1.5% Si and "» / 9 [C] + 2 [Mn]> 25 is sufficient, or a steel that continues less than 15% Cr, less than 5% Ni, less than 1% Ca, less than 5% Mo and small amounts of Ti, Nb, V, W and Zr contains is particularly as non-magnetic High Mn steel suitable. Such a steel has, as indicated in the above-mentioned patent specification has very good properties, in particular it can be used as non-magnetic steel rods in concrete structures be used.

The shape of the non-magnetic steel material is not particularly limited either. The shapes that are in Concrete structures used include straight steel bars, different shaped steel bars, steel shapes for steel plaiisn, steel frame materials and other shapes of various products, such as Wires and fibers. In any of these forms, the beneficial effects of the present invention can be obtained

when a coating layer is formed on the surface.

The following examples illustrate the invention.

Using the non-magnetic steels with

Table I.

Various coatings are prepared from the compositions listed in Table I, and then the anti-rust properties and the insulating properties are tested.

Designation compositions of the material samples (";.) ^Mln 8 C Si Mn Cr

Ni Mo

Total N only ΛΙ // *)

A.
B.
C.
D.

0.87
0.54
0.56
0.43
0.46
0.32
0.47

0.32

0.30
0.58
0.44
0.59
0.30
0.31

14.26 16.90 16.87 15.00 17.05 18.00 16.05

5.40 6.10 4.00

3.88

2.04 0.20

0.31

0.0103

0.2600
0.2130
0.0110
0.0117
0.2041
0.011

0.022 0.006 0.002 0.035 0.028 0.007 0.020

1.006 1.007 1.007 1.010 1.009 I. (X) 7 1.011

*) Magnetic permeability with a magnetic l ^; eldintensiliit Min 5 7W A / m after the solution treatment by ^oil: rhit / en hot

(a) Anti-rust or rust protection test

The steels A to F in Table I are hot-rolled to straight bars with a diameter of 10 mm, and then let them cool. The surface coatings listed in Table II are then applied and then they are tested in ambient atosphere and artificial sea water. »>

The coating procedures are as follows:

No treatment - used to descaling pickled;

Anti-rust oil - pickling is used for descaling, π and then the following is painted with a water-soluble anti-rust oil:

Epoxy resin coating - for descaling it is treated with a sandblasting fan, and then it is with an electrostatic powder of the acid anhydride type bisphenol epoxy resin which sets, painted, and then at 240 ° C for 30 minutes to form a film with a Thickness of about 170 to 200 μm baked or fired;

Vinyl chloride resin coating - for descaling is pickled, then preheated to 100 ⁰ C, coated with an electrostatic powder of vinyl chloride resin and 30 and baked at 320 ° C to form a film having a thickness of about 170μιη baked min.

The test results are shown in Table M.

Tabel Il Base material μ I month in the / I 6 months in the μ 12 months in the I. Stole- Kind of overture the atmosphere the atmosphere the atmosphere I. p raw Amount of Amount of Amount of Amount of μ formed. 1.006 formed. 1,022 formed. 1,153 formed. Rust, mm 1.006 Rust, mm 1.006 Rust, mm 1.006 Rust, mm 0 1.005 0.033 1.006 0.286 1,018 0.51! 1,254 ■ is A. no treatment 0 1.006 0.004 1.006 0.008 1.005 0.012 1.007 I. Λ Zn plating 0 1.005 0 1.005 0.025 1.005 0.224 1,118 A. Anti-rust oil 0 1.007 0 1,020 0 1.137 0 1.006 - @ A. Epoxy resin 0 1.006 0 1.007 0 1.007 0 1.005 A. Vinyl chloride resin 0 1.006 0.031 1.007 0.228 1.011 0.474 1,238 B. no treatment 0 1.007 0.002 1.007 0.006 1.006 0.008 1.007 B. Zn plating 0 1.007 0 1.006 0.017 1.006 0.206 1.109 B. Anti-rust oil 0 1.007 0 1.031 0 1.184 0 1.006 B. Epoxy resin 0 1.007 0 1.006 0 1.008 0 1.007 B. Vinyl chloride resin 0 1.006 0.026 1.007 0.255 1.010 0.423 1.266 C. no treatment 0 1.008 0.001 1.007 0.004 1.007 0.006 1.007 C. Zn plating 0 L006 0 1.007 0.022 1.008 0.194 1.104 C. Anti-rust oil 0 1.010 0 1,028 0 1,112 0 1.007 C. Epoxy resin 0 1.008 0 1.009 0 1.009 0 1.007 C. Vinyl chloride resin 0 1.009 0.022 1.010 0.169 1.017 0387 1.227 D. no treatment 0 i, 009 0.001 1.009 0.005 1.009 0.009 1.009 D. Zn plating 0 1.009 0 1.010 0.019 1.009 0.115 1.101 D. Anti-rust oil 0 0 0 η
U 1, OiG D. Epoxy resin 0 0 0 0 1.009 D. Vinyl chloride resin

continuation

Stole- Type of pull (! round material .009 I month in de Γ , 021 6 months in the .165 12 months in lcr l'robe , 009 the atmosphere , 009 the atmosphere , 009 the atmosphere Amount of / .0Ti Amount of / .009 Amount of / , 012 Amount of / {! child. . (KW formed. .009 hild. , 009 hild. Rust, mm .009 Rust, mm , 008 Rust, mm , 009 Rust, mm E. no treatment 0 .007 0.035 , 023 0.213 , 158 0.403 , 262 E. Zn plating 0 .007 0.001 , 007 0.005 .007 0.006 .009 E. Roslschuizöl 0 .007 0 .006 0.016 , 007 0.220 .116 E. Epoxy resin 0 .007 0 .007 0 , 007 0 .010 E. Vinyl chloride resin 0 .007 0 , 007 0 , 007 0 .008 I. no treatment 0 .011 0.036 .029 0.301 .160 0.572 .266 I. / n-l'lating 0 .011 0.002 .010 0.004 , 010 0.011 .006 I. Rust protection / oil 0 .010 0 .010 0.010 .017 0.136 .100 1 Epoxy resin (1 .010 0 .010 0 , 010 0 .007 I. Vinyl chloride h 0 .011 0 .010 0 .010 0 .007 Ci no treatment 0 0.002 0.202 0.409 .264 (i Zn plating 0 0.002 0.006 0.008 .011 Anti-rust oil I) 0 0.012 0.128 , 099 Ci Epoxy resin 0 0 0 0 .010 Ci Vinyl chloride resin 0 0 0 0 .011

Table II (continued)

SiMhI- ArI des I her / iigs (irundmaicriiil . (K) 6 I Monal in art .107 6 months in art .418 12 months η artificial / ' 'raw . (X) 6 fresh lake water .006 fresh lake water 1.006 lichcm lake water Amount of / . (ΗΪ5 M-'nge .in / .100 Amount of / .342 Amount of hild .006 L-picture. .006 formed. .006 formed 2,004 Riisi. mm .005 Rust, mm .005 Rust, mm 1.006 KiTSt. mm 1.007 Λ no behavior inditing 0 .007 0.164 .100 0.835 .365 1,705 1,763 Λ / n-l'lating 0 .006 0.015 .006 0.025 1.009 0.030 1.005 Λ Rnstschut / oil 0 .006 0.153 .097 0.645 , 318 1,662 1.005 Λ Epoxy resin 0 .007 0 .007 0 .006 0 1,812 Λ Vinyl chloride resin 0 . (X) 7 0 .006 0 .007 0 1,017 B. no treatment (I. .007 0.135 .104 0.844 .403 1,640 1,672 B. Zn plating 0 .007 0.011 .007 0.032 .007 0.058 1.007 B. Roslschuizöl 0 .006 0.104 .101 0.592 .402 1,603 1.006 B. Epoxy resin 0 .008 0 .007 0 .008 0 1.996 B. Vinyl chloride resin 0 .006 0 .008 0 .007 0 1.007 C. no treatment 0 .010 0.159 .105 0.801 .412 1.611 2,000 C. Zn plating (I. .008 0.010 , 0? 0 0.028 , 009 0.040 1.007 C. Anti-rust oil 0 .009 0.118 , 089 0.795 , 333 1,647 1.007 C. Epoxy resin 0 .009 0 .010 0 .009 0 2,001 C. Vinyl chloride resin 0 .009 0 .009 0 , 009 0 1.010 D. no treatment 0 .009 0.160 , 099 0.877 .423 1,673 1,604 D. Zn plating 0 .009 0.012 , 009 0.030 , 010 0.044 1.009 D. Anti-rust oil 0 .008 0.106 , 103 0.658 , 338 0.537 1.009 D. Epoxy resin 0 .009 0 .009 0 .008 0 1,761 D. Vinyl chloride resin 0 .009 0 , 009 0 , 008 0 1.010 E. no treatment 0 .007 0.148 , 102 0.882 , 422 1,614 1,600 E. Zn plating 0 .007 0.009 .007 0.019 .006 0.033 1.009 E. Anti-rust oil 0 .007 0.114 .103 0.679 344 1.405 1.008 E. Epoxy resin 0 , 007 0 .007 0 £ 06 0 1.915 E. Vinyl chloride resin 0 .007 0 .006 0 .006 0 1.007 F. no treatment 0 0.154 0.843 1,713 ! .670 F. Zn plating 0 0.017 0.023 0.038 1.007 F. Anti-rust oil 0 0.138 0.685 ! .620 1007 F. Epoxy resin 0 0 0 0 F. Vinyl chloride resin 0 0 0 0

Art ilcs cover 9 GrunOmalcriMl / ' 29 08 575 η; / 1.107 10 I. , 436 12 months in artificial 1.010 .011 lichem Seew \ sscr Amount of Rust, mm 1.098 .401 Amount of gebilcl. 1.011 I month in artificial 0.162 1.010 6 months in art , 010 gebilil Continuation Rust, mm 1.011 licheni lake water 0.011 1.011 fresh lake water .011 Rust, mm stole no treatment 0 1.010 Lot; 0.121 Amount of ι 1.630 1,785 sample Zn plating 0 1.010 gebilil. 0 Gebikl. 0.030 1.010 Anti-rust oil 0 1.011 0 Rust, mm 1,494 1,615 Epoxy resin 0 0.857 0 1.011 Vinyl chloride har7; 0 0.019 11th 1.010 G 0.734 G 0 G 0 ü G

To determine the amount of rust formed, the weight of the sample (with a diameter of 10 mm) before carrying out the test and during the remainder of the test. The Rosi becomes inii one aqueous solution of ammonium citrate is removed, the weight of the sample is determined, and the weight difference is converted into the average reduction in Diameter (mm) of the sample converted.

The magnetic permeability is measured with a magnetic balance of the sample with a diameter of 10 mm and a length of 30 mm certainly.

The results listed in Table II became found that when the uncoated sample was left to stand in an atmosphere for one month, the increase in μ due to the Rust formation, already exceeds 1.02. The sample painted with the rust preventive oil shows an essential one more favorable effect in the atmosphere, but practically observed in artificial lake water no favorable influence. On the other hand, show the zinc-plated, epoxy resin and vinyl chloride resin coated materials give favorable results both in the atmosphere and in artificial sea water. In particular, the two resins did not produce rust in either of the tests. It is therefore found that JO

any increase in magnetic permeability of the material is effectively connected by these materials.

(b) Isolation test

Deformed steel rods D 22 (nominal diameter 22 mm) are produced by hot rolling steels A, C and D according to Table I and coated on their surface with the materials listed in Table III. Then the electrical resistance of each of these bars is determined according to the method shown in FIGS. 1 and 2 described test procedure determined. Specifically, test pieces 1 with a length of 700 mm and test pieces Γ with a length of 900 mm are arranged in a square, and the joints 2, 3 and 4 are connected with low-carbon steel wires or nylon threads, and the joint 5 is insulated with rubber hoses. This arrangement is embedded in a concrete slab 6 (800 × 800 × 50 mm), which is shown in FIG. 2, and the electrical resistance between ends A and B is determined with a resistance meter 7. Five concrete slabs made in this way were tested.

The test results are shown in Table III. Table III Insulation test results

Steel type of coating
sample

Type of connection

at the junction

Electrical resistance between
AB (Q)

12 3 4 5

A Steel bar D 22 as rolled

Steel rod D 22, painted with tar (50 / <m thick) Steel rod D 22, coated with epoxy resin Steel rod D 22, coated with vinyl chloride resin

C Steel bar D 22 as rolled

Steel rod D 22, painted with tar (50 / im thick) Steel rod D 22, coated with epoxy resin Steel rod D 22, coated with vinyl chloride resin

connected with soft steel wire connected with nylon cord connected with soft steel wire connected with nylon cord connected with soft steel wire connected with nylon cord connected with soft steel wire connected with nylon cord

connected with soft steel wire connected with soft steel wire

connected with soft steel wire connected with soft steel wire

2.5

3.8 40

20th

continuation

Chair ΛΠ of ahout / coll
sample

ArI of the connection

iin the connection socket

Electrical contradiction / wipe Λ-Β (ϋ)

I 2 .1 4 5

D Steel bar D 22 as rolled

Steel rod D 22, painted
with tar (50 // m thick)
Steel rod D 22, coated
with epoxy resin
Steel rod D 22, coated
with vinyl chloride resin

connected with soft steel wire
connected with soft steel wire

connected with soft steel wire
connected with soft steel wire

<1 <I <I <I <

OO OO OO OO OO

OO OO OO OO OO

DO CT OC ~ O CO

It was found that the electrical resistance at the joint in the steel bar as rolled is very small and that the possibility of a closed electrical circuit being formed is the produced by contact of the steel rods with each other is very large. In one case, the coating layer was. which had been made by painting with tar. when connecting with a steel wire with low The carbon content was interrupted and the insulation therefore failed. This is therefore included as an insulating cover not suitable for an actual working process.

The electrical resistance of all synthetic resin coatings is infinite; H. the coatings are excellent insulators, and their good effects have been confirmed.

Together with the results of the rust protection tests described above, it is evident that the synthetic resin coatings are excellent for rust protection and insulation. In the above mentioned For example, the epoxy resin and the vinyl chloride resin are examples of usable resins. The same Effects can also be obtained by making the aforementioned other types of Synthetic Resin coatings used. Such synthetic resin coatings have very good mechanical properties against bending or impact, and therefore they are excellent coating materials for non-magnetic steel materials.

For this I Hlatt / eichnunuen

Claims (4)

Patent claims: J. Use of steel components made of a non-magnetic steel with a high Mn content, the have an electrically insulating cover, for embedding in concrete, mortar or cement masses. 2. Use of steel components made from a non-magnetic steel with a high Mn content according to claim 1, with an electrically insulating ι ο coating made of a synthetic resin or rubber. 3. Use of steel components made from a non-magnetic steel with a high Mn content according to claim 1 or 2 with a steel surface descaled before coating. ι s 4. Use of steel components made from a non-magnetic steel with a high Mn content according to any one of claims 1 to 3, wherein the steel components also have an anti-rust coating exhibit.