JPS60174855A - Heat and corrosion resistant steel wire having high strength and ferromagnetism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

The present invention relates to a high-strength ferromagnetic heat-resistant and corrosion-resistant steel wire with particularly excellent warm strength. Recently, much work has been carried out to explore the geological conditions deep underground. FIG. 1 is an explanatory diagram showing how a logging cable is used in, for example, a well for geothermal power generation. As shown in the figure, a well excavated vertically deep underground (1), a probe for exploring hot spring veins near the bottom (2), etc., (3) a probe suspended from the entire ground surface into the well (1), A logging cable (4) is used. Such logging cables use heat-resistant and corrosion-resistant steel wires, but they are used in high-temperature environments where they are exposed to highly corrosive gases such as sulfur dioxide gas, and the wells are as deep as 10 km, so they cannot be used near the surface. Since a stress close to 80° is applied due to its own weight alone, the logging cable is required to have high corrosion resistance and a high degree of warm strength. Furthermore, the cable itself is required to be ferromagnetic in order to be used as part of a magnetic exploration system. In addition to the above, there is also an example of an exploration cable for oil wells, but this is also used in almost the same environment as the above. The conditions for the characteristics of steel wires that can sufficiently cope with such usage environments are summarized as follows. ■ It can maintain more than 80% of its strength at 400℃ ■ It is ferromagnetic and has crush resistance comparable to that of stainless steel Ferritic and austenitic stainless steels are conventionally known for use in logging cables. Furthermore, there are superalloys such as Inconel, etc. However, in light of the above requirements, first of all, these are insufficient in terms of strength. Figure 2 shows 5uisao, which is a typical example of conventional heat-resistant and corrosion-resistant steel wire.
4 is a diagram showing the relationship between the tensile strength at 400°C and heating time of a drawn wire material of autenite stainless steel. In the curve [F] where the degree of wire drawing is 0%, the tensile strength is 60%.
Even in the curve (Q) with a degree of wire drawing of 80%, it decreases to 80z or less when the heating time exceeds 8 hours. In this way, conventional heat-resistant and corrosion-resistant alloys such as stainless steel cannot provide the strength that satisfies the above conditions, and furthermore, except for ferritic alloys, they do not have magnetism, and all of them are high alloys made of MOr threads and are expensive. Therefore, there was also the problem of high costs. The importance of such heat-resistant and corrosion-resistant steel wires with excellent warm strength is not limited to geothermal power generation wells and oil well drilling, but is expected to expand to a wider range of underground exploration in various fields in the future. , its development is urgently needed. Therefore, the object of the present invention is to obtain a heat-resistant and corrosion-resistant steel wire having characteristics that meet the above-mentioned conditions.゛The present inventors believe that a clad structure combining alloy steel and stainless steel is effective for such purposes, and have conducted various experiments and research on the premise of adopting such a clad structure. If the composition of the core material is appropriately selected and austenitic stainless steel is used as the cladding material, the cladding steel wire will have strength characteristics and ferromagnetism that meet the above-mentioned requirements, and will also have the same high corrosion resistance as austenitic stainless steel. We found that it is possible to obtain That is, the gist of the present invention is that C0,7 to 1.
1%, Si0.2-2.0%, Mn 0.4-2.03
'6, erO65~2.0%, AtO, 1% or less, Mo
The #J thermally erodible steel wire has high strength ferromagnetism and is composed of a core material with a composition of Fe and unavoidable impurities and a cladding material of austenitic stainless steel. Specifically, the composition of the core material is such that, as a clad steel wire, a warm strength of 80 or more at 400° C. and ferromagnetism are ensured. That is, the steel wire of the present invention ensures strength and magnetism through the core material and maintains corrosion resistance through the austenitic stainless steel cladding surrounding the core material. Figure 4 shows test steel wires (drawn wires) with various cladding ratios using combinations of alloy steel (core material D) and cladding material consisting of USB 04 autenite stainless steel having compositions within the scope of the present invention. Machining rate 80%, diameter IM/ ) 4
The relationship between load stress and heating time at 00℃ is shown, (g)
, (G), and (G) are the thicknesses of the clad material in the umbrella diameter of 0 (
δ), that is, the cladding ratio (2a/D) (third
(See figure (cross-sectional view)) are different, (G) is 20% clad ratio, (G) is 40%, and CG) is 5%.
0%. In the figure, when the cladding ratio is approximately 40% or less, a strength of 8 oz at 400° C. is ensured. At this clad ratio of 40% or less, the original magnetism of the core material is not impaired, and the clad steel wire exhibits ferromagnetism as a whole. As described above, according to the present invention, it is possible to achieve the desired temperature of 400°C.
It is possible to simultaneously secure ferromagnetic properties and corrosion resistance on a stainless steel level. In addition, since this type of steel wire is generally used for final use in the state of cold working (wire drawing), its strength is also affected by the degree of working in the final cold drawing. Therefore, with regard to the strength of the steel wire for application of the present invention, it is necessary to take into consideration not only the above-mentioned cladding ratio but also the working degree given in the final wire drawing. For the above-mentioned logging cable, the final wire drawing degree is 80% after bending (7
5 to 85 bulk), but assuming this condition, the property of exhibiting a warm strength of 8 oz at 400°C can be stably obtained by setting the shuffled ratio to 40% or less, as described above. be able to. Next, the reason why the components of the core material are limited as described above in the invention will be explained. C: The most important component for ensuring strength. If it is less than 0.7%, it will not be possible to secure the final target warm strength of 8 oz or more at 400°C, and if it exceeds 1.1%, the drawability will deteriorate. Therefore, it was set at 0.7 to 1.1%. Sl: An effective component for increasing high-temperature strength, but with a content of 0.
If it is less than 2%, hardenability will be insufficient, and if it exceeds 2.0%, the deterioration of ductility will be significant. Mn: Improves hardenability and is effective in strengthening tensile strength; however, if it is less than 0.4%, hardenability is insufficient;
If it exceeds 0%, pearlite will become coarser, so 0.2
~2.0%. Cr: A necessary component to ensure high-temperature strength. If it is less than 0.5%, the strength will be insufficient, and if it is added in excess of 2,0'), the strength will be higher than necessary and it will be difficult to process. The content was set at 0.5% to 2.0% because it becomes difficult. MO = 0.8% or less was added in a necessary amount depending on the concentration of Cr in order to compensate for hardenability and to prevent deterioration of ductility due to segregation of P'pCr. At: Added as a deoxidizing agent during the steelmaking stage, it forms a compound with N and is effective in suppressing aging phenomena. However, if it exceeds 0.1%, it will cause deterioration of ductility.
．． It was set to 1% or less. The stainless steel for the cladding material was limited to autenite Nutenrenu steel because the Huefi i-based nutenless steel has the characteristic of being brittle at 475°C, so the cladding material for the steel wire of the present invention, which emphasizes ensuring warm strength, was selected as the cladding material. This is because it is not appropriate. Below, examples will be given to clarify the effects of non-invention. Table 1 Using 5US804 stainless steel with the ingredients shown in Table 1 as the cladding material and alloy steels with the various ingredients shown in Table 2 as the core material, various stainless steels of uninvented examples and comparative examples were manufactured in the manufacturing process shown in Figure 5. A test steel wire with cladding was manufactured. In producing the clad billet, the dimensions of the core billet and clad pipe were selected so as to achieve the target clad ratio. For example, 20! If you aim for a cladding ratio of X, 80w1! f core material billet and wall thickness,
10am. A clad billet was made using a clad pipe with an outer diameter of 10 (1!/).Also, the final steel wire dimensions were all 1.0 in diameter.
M/l! :L, 1.0w1f wire drawing degree was 80%. The heat treatment (1) in the step is solution heating (100
0°C x'1hr) → Isothermal transformation treatment (600°C lead bath x'8
m1n immersion) heat treatment (2) is patenting treatment (95
0°C x 16 min → 600°C lead bath x 3 min). The presence or absence of magnetism as well as the mechanical properties of the test steel wires of the above-mentioned examples of the present invention and comparative examples were investigated, and the results are shown in Table 2. The results will be explained by dividing into groups A to E shown in Table 2. For the test steel wires of Group A, the influence of the C content of the core material was investigated. If it is below the lower limit of the present invention range, the strength will be insufficient, and if it exceeds the upper limit, the wire drawability will deteriorate. In the test steel wires of Group B, the influence of the 81 content in the core material was investigated. If the lower limit of the present invention range is below, the strength will be insufficient, and if the upper limit is exceeded, the ductility will decrease. For the test steel wires of group 0, the influence of the Mn content of the core material was investigated. If the range is below the range of the present invention, the strength will be insufficient, and if it exceeds the upper limit, the ductility will decrease and sufficient strength will not be obtained. For the test steel wires of Group D, the influence of the Cr content in the core material was investigated. If it is below the lower limit of the present invention range, the strength will be insufficient, and if it exceeds the upper limit, the wire drawability will deteriorate. For the test steel wires of Group E, the influence of the cladding ratio on the properties of the steel wires was investigated. As the cladding ratio increases, the warm strength tends to decrease;

[Final wire drawing degree: 80%] In order to obtain a warm strength of 40 (1-78 oz), a cladding ratio of approximately 40% or more is required.As is clear from the above explanation, the steel wire of the present invention , 40
It can be configured to have a strong warm gFsoz and ferromagnetic properties at 0°C, as well as corrosion resistance comparable to that of stainless steel, and is cheaper than conventional heat-resistant and corrosion-resistant steel wires, making it suitable for geothermal power generation wells and oil well inspections. This steel wire has excellent practicality as a material for layered cables.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing how logging cables are used in wells for geothermal power generation, and Figure 2 shows the relationship between tensile strength at 400°C and heating time of SUS'804 austenitic stainless steel wire rod. Figure 3 is a cross-sectional view of a stainless clad steel wire, and Figure 4 is a cross-sectional view of a stainless clad steel wire drawn to a diameter of 1.0 M$ with a wire drawing degree of 80% with various crat ratios. FIG. 5 is a diagram showing the relationship between applied stress and heating time at °C, and is a process chart showing the manufacturing procedure of a clad steel wire used in a test to confirm the effects of the present invention. 1: Well, 2: Hot spring wind, 8: Exploration device, 4: Logging caple Fig. 1 Fig. 2 → Added axis # M (Hr) Fig. 3

Claims (1)

[Claims] (1) Co, r ~ l, 1%, S'10.2 ~ 2.0
%, Mn 9.4-2.0%, Or 0.5-2.0%,
Contains A70.13'6 or less, Mo 0.80% or less,
A heat-resistant and corrosion-resistant steel wire having high-strength ferromagnetism, characterized in that it consists of a core material whose composition is composed of Fe and unavoidable impurities, and a cladding material of austenitic stainless steel surrounding the core material.