JPS62116755A - Steel for stainless razor blade - Google Patents

Abstract

PURPOSE:To obtain a steel for a stainless razor blade having superior corrosion resistance and a long life by adding Mo and/or Co and Cr to a steel to ensure corrosion resistance and by further adding Si and V in combination with the Mo and/or Co to prolong the life of a blade made of the steel. CONSTITUTION:The composition of a steel for a stainless razor blade is composed of, by weight, 0.55-0.75% C, 0.4-1% Si, 0.2-1% Mn, 12-15% Cr, <0.01% S, <0.02% acid-sol. Al, 0.05-0.4% V, 0.4-2% Mo and/or 1-5% Co and the balance Fe with inevitable impurities.

Description

[Detailed description of the invention]

(Industrial Field of Application) The present invention relates to steel for razor blades, and more particularly to stainless steel for razor blades with excellent corrosion resistance and longevity. (Prior art and problems) Conventionally, high carbon, high chromium steel, low carbon, high chromium steel, etc. have been used as materials for safety razor blades or disposable razor blades. Because of its high C content, it has poor corrosion resistance, and although low carbon, high chromium steel has satisfactory corrosion resistance, it has the disadvantage of poor heat treatment hardness, wear resistance, etc. due to its low C content, and short service life. there were. For this reason, corrosion resistance can be improved by increasing the amount of Cr added and actively adding AQ, or by adding a large amount of Si and adding AQ.
Various attempts have been made, such as adding Q to prevent a decrease in hardness during tempering and improve toughness, or to extend life by improving corrosion resistance. However, stainless steel for razor blades is usually cold-rolled and quenched to sub-zero, then the blade is processed and then coated with Teflon coating. Since the tempering is carried out at 0°C, it is necessary to ensure hardness, toughness, etc. after so-called tempering, and furthermore, it is necessary to extend the lifespan so that it can be used many times. In this respect, none of the conventional steels for razor blades has sufficiently satisfactory corrosion resistance and service life. (Objective of the Invention) The object of the present invention is to eliminate the drawbacks of the above-mentioned prior art and to provide a stainless steel for razor blades that has excellent corrosion resistance and long life. (Structure of the Invention) In order to achieve the above object, the present inventors conducted repeated research to find a method for imparting sufficient corrosion resistance and long life to martensitic chromium stainless steel for use in razor blades. Corrosion resistance can be sufficiently ensured by the addition of Go and/or Cr, and the above-mentioned Mo and/or
Alternatively, it has been found that the lifetime can be extended by adding Go and SL in combination with V. That is, the stainless steel for razor blades according to the present invention has a weight ratio of c:o,s of 5 to 0.7 (the same applies hereinafter).
5%, Si: 0.4-1.0%, Mn: 0.2-1.0
%, Cr: 12.0-15.0%, S: 0.01% or less, 5oQAQ: 0.02% or less, and V: 0.05-0
．． 4%, further Mo: 0.4-2.0% and Co:
1. The present invention is a stainless steel razor blade steel with excellent corrosion resistance and long life, characterized by containing one or two of O~5.0%, with the remainder consisting of Fe and unavoidable impurity elements. The present invention will be explained in detail below based on examples. The adjustment of the composition of the steel of the present invention was obtained as a result of further experiments based on the above findings, and the reasons for limiting each component and its content are as follows. C is an element necessary to ensure hardness during quenching and tempering, and for this purpose, 0.55% or more is required, but if it is contained in excess of 0.75%, corrosion resistance cannot be ensured. As it disappears, giant carbides tend to crystallize, reducing toughness. In order to prevent the crystallization of giant carbides as much as possible, the content should be kept at 0.75% or less. Si needs to be added in an amount of 0.4% or more to improve tempering softening resistance and ensure hardness during tempering, and the composite addition of V, Mo, and /Go described below will extend life. It has an effect. However, if it is added in excess of 1.0%, cold working (rolling) to make it extremely thin becomes extremely difficult, so the content is set in the range of 0.4 to 1.0%. Mn must be added for deoxidation and desulfurization. Furthermore, it is added to control the morphology of inclusions such as sulfide (MnS), and in order to achieve these effects, 0.2
% or more is required. The addition of Mn promotes deoxidation and desulfurization and reduces the amount of inclusions such as MnS, AQ, and 03 in the steel, but at the same time, these inclusions are deformed during hot rolling.
It is in a form that is easily crushed, and the influence of inclusions, which are sometimes the starting point of chipping, can be eliminated, especially when using a blade. but,
If it is added in an amount exceeding 1.0%, retained austenite increases and hardness decreases, so in order to suppress retained austenite and prevent a decrease in hardness, it is desired that the content be 1.0% or less. Cr is an important element for ensuring corrosion resistance, and for this purpose it is necessary to add 12.0% or more. However, if it exceeds 15.0%, the hardness decreases, so to prevent this, the content is set to 15.0% or less. S and 5ofiAQ are impurities in steel, and in the past, they were not understood due to their relationship with the characteristics of razor blade steel. However, in the present invention, S2 is 0.01% or less and 5ofiAQ: 0.02%. By regulating the following:
This effectively prevents the occurrence of sharpening caused by an increase in sulfides (MnS) and oxides (80203). In addition, in order to further increase such effects, it is preferable to reduce S to 0.005% or less and soΩAQ to 0.011% or less. It is. (2) is added in an amount of 0.05% or more since it can improve the life by improving wear resistance. However, adding (2) alone does not have much effect, but adding an appropriate amount of Si as described above and Mo and/or G as described below. It is possible to significantly improve lifespan only by adding it together with an appropriate amount of . but. If added in a large amount exceeding 0.4%, clogging occurs during polishing with a whetstone and the polishing performance deteriorates, so the content should be 0.4% or less. Mo and Co can significantly improve corrosion resistance compared to when they do not contain them, and can also ensure sufficient hardness after tempering (approximately 300°C or higher), as well as the toughness required during cutting or use. These elements can be sufficiently secured, and for this purpose Mo: 0.4 to 2.0% and Co: 1.0%. O~5.
It is necessary to add one or two of them at 0%. Note that if each element exceeds the above upper limit, cold working (rolling) to make it extremely thin becomes extremely difficult. As explained above, the present invention is based on the premise that the content of S and 5oQAQ, which are usually treated as impurities, is regulated, and furthermore, appropriate amounts of Si, V, and M are contained. By adding Cr and/or Co in combination, the life of the razor blade can be significantly improved, and further, along with the addition of Cr and the like, the corrosion resistance can be further improved. (Example) Test steel having the chemical composition (wt%) shown in Table 1 was melted. Cold-rolled materials were obtained by conventional methods, and each was subjected to corrosion resistance tests,
Hardness tests and life tests were conducted. In addition, as a corrosion resistance test, test pieces were tested at 1070℃
0.5hr・Oil quenching → Sub-zero treatment (-78℃X0,
After applying each treatment (tempering 400'' CX 1 hr, air cooling), a humidity test was performed under the conditions of 49℃ x 96 hr, and judgment was made based on the presence or absence of rust and the degree of rust.In addition, as a life test , 0, i n+m cold-rolled material is quenched at 1050-1080°C → sub-zero treatment (-
78°C x 0.5hr) → Machining the blade → After applying Teflon coating (370'C), Honda method cutting test (load 500g, total number of sheets cut until 300 sheets of paper could not be cut) (to evaluate the lifespan), and the total number of sheets cut was determined. These results are shown in Table 2.

[Left below]

As can be seen from Table 2, the steel of the present invention has excellent corrosion resistance, and in particular, the service life is significantly improved. On the other hand, in the comparative example, even if the corrosion resistance is good (No, 5.6), the S and 5oQAQ amounts are outside the range of the present invention, so the life improvement effect is insufficient, and the S
Those with a small amount of i and containing neither V, Mo nor Co (No. 4) are inferior not only in corrosion resistance but also in life. (Effects of the Invention) As detailed above, according to the present invention, it is possible to provide stainless steel that is excellent in both corrosion resistance and lifespan required for razor blades, and in particular, the lifespan can be significantly improved, so that it can be used many times. This allows the use of the following without any problems.

Claims (1)

[Claims] Weight percentage: C: 0.55-0.75%, Si: 0.4
~1.0%, Mn: 0.2~1.0%, Cr: 12.0
~15.0%, S: 0.01% or less, solAl: 0.
02% or less and V: 0.05 to 0.4%, and further contains M
Corrosion resistance and lifespan characterized by containing one or two of O: 0.4 to 2.0% and Co: 1.0 to 5.0%, with the remainder consisting of Fe and inevitable impurity elements. Superior stainless steel for razor blades.