JPH0262116B2

JPH0262116B2 -

Info

Publication number: JPH0262116B2
Application number: JP29871685A
Authority: JP
Inventors: Kanichi Tanaka; Kensuke Hidaka
Original assignee: Fukuda Kinzoku Hakufun Kogyo Kk
Current assignee: Fukuda Kinzoku Hakufun Kogyo Kk
Priority date: 1985-12-27
Filing date: 1985-12-27
Publication date: 1990-12-21
Also published as: JPS62156095A

Description

[Detailed description of the invention]

〔産業上の利用分野〕本発明は、各種プラント内の摺動部表面硬化肉
盛用として用いられる、靭性及び耐熱性を兼ね備
えたNi基肉盛合金に関するものである。〔従来の技術〕従来、硬化肉盛用Ni基合金としては、AWS−
NiCr−Ａ〜NiCr−Ｃに代表される自溶合金があ
るが、これらの合金は靭性に乏しいため、大型の
母材や熱膨脹率の差が大きい母材に硬化肉盛する
際、肉盛層に「割れ」を生じる欠点があつた。本発明者らは、こうしたことから先に重量で
Cr5〜15％，B0.05〜1.5％，Si5〜７％，Fe30％
以下，C0.05〜1.5％，W5％以下で残部が実質的
にNiからなる高靭性Ni基肉盛合金（以下「先の
発明合金」と呼ぶ）を開発、特許出願した。（特
公昭59−35422）しかしながら、上記先の発明合金は従来の自溶
合金に比べて飛躍的に靭性の向上が得られたもの
の、700℃〜900℃といつた高温域での使用におい
ては、従来の自溶合金と同様、合金の軟化現象が
起こり、このための温度領域での使用は実用上不
可能であつた。〔本発明が解決しようとする問題点〕本発明は、上記の問題点を解決する目的で、
Co基肉盛合金に匹敵する靭性及び耐熱性を有し、
かつ高価な元素を含まず経済性にも優れたNi基
肉盛合金を提供することにある。本発明者らは、先の発明合金をベースに、種々
の元素添加による特性向上の研究を進めた結果、
Alを所定範囲内で含有させることにより、硬さ
及び衝撃強さが向上すると同時に、耐熱性も向上
することを見出した。〔問題を解決するための手段〕本発明の合金は(1)重量でCr5〜15％，B0.05〜
1.5％，Si5〜７％，Fe20％以下，C0.05〜1.5％，
Al0.5〜５％を含有し、残部が実質的にNiからな
ることを特徴とする硬化肉盛用Ni基高靭性耐熱
合金。(2)重量でCr5〜15％，B0.05〜1.5％，Si5〜
７％Fe20％以下，C0.05〜1.5％，Al0.5〜５％，
W5％以下を含有し、残部が実質的にNiからなる
ことを特徴とする硬化肉盛用Ni基高靭性耐熱合
金である。〔作用〕次に本発明の合金の成分元素の含有量限定理由
について述べる。以下％は重量％を示すものとす
る。 Al0.5〜5.0％ Alは本発明において最も重要な元素で、Alを
0.5％の範囲で含有させたとき、硬さ及び衝撃強
さが共に向上し、Al2％のとき硬さ及び衝撃強さ
が共に最大値を示す。本発明の合金に含有されたAlは、合金の基質
部を形成しているNi固溶体中に入り、Ni₃Alで示
される金属間化合物を生成し、合金の強化を果た
している。 Alの含有量が0.5％以下となると、この効果が
なくなり、５％を超えると含有の効果がなくなる
ばかりでなく、肉盛溶接性にも悪影響を及ぼす。以上の理由から、Al含有量は0.5〜５％と限定
した。 Cr5〜15％ Crは耐熱性、耐食性を維持する上で必須な元
素である。この目的には、最低５％を必要とする
が、Crの含有量が15％を超えるとＢ，Ｃとの間
に金属間化合物を形成し、合金の靭性が低下す
る。以上の理由から、Crの含有量は５〜15％と限
定した。 B0.05〜0.5％・Si5〜７％Ｂ及びSiは共に高硬度の金属間化合物を形成
し、合金中に析出し、合金の硬さを向上させると
ともに、肉盛性を改善する働きを有する。B0.05
％以下，Si5％以下となると、硬さがHC35以下と
なるとともに、肉盛中に自溶性の無いスラグを多
く発生し、肉盛溶接性が害される。またB1.5％
以上，Si7％以上になると、合金の靭性が低下す
る。以上の理由から、Ｂ，Siの含有量はB0.05〜1.5
％，Si5〜７％と限定した。 Fe20％以下 FeはNiと同族の元素で、しかもNiに比べて安
価なため経済性から、できるだけNiの代替元素
として多く含有させるのが好ましいが、Feの含
有量が20％を超えると、合金の硬さが低下する。以上の理由からFeの含有量は20％以下と限定
した。 C0.05〜1.5％Ｃは合金の硬さを向上させる働きを有するが、
Ｃの含有量が0.05％以下では、硬さが低くなり、
また1.5％を超えると、合金の靭性が低下する。以上の理由からＣの含有量は0.05〜1.5％と限
定した。 W5％以下Ｗは合金の基質部に分散し、硬さ及び耐熱性を
向上させる働きを有するが、Ｗの含有量が５％を
超えると、合金の靭性が低下する。以上の理由からＷの含有量は５％以下と限定し
た。〔実施例〕次に本発明に基づく実施例として、請求の範囲
内での組成で製造した本発明の合金と比較例の合
金とを実験した結果を説明する。第１表は、本発明の合金（11種類）と比較例の
合金（３種類）の組成、硬さ（鋳造材硬さ）、衝
撃強さを示したものである。 [Industrial Field of Application] The present invention relates to a Ni-based overlay alloy that has both toughness and heat resistance and is used for hardfacing the surface of sliding parts in various plants. [Conventional technology] Conventionally, AWS-
There are self-fluxing alloys represented by NiCr-A to NiCr-C, but these alloys have poor toughness, so when hardfacing a large base material or a base material with a large difference in coefficient of thermal expansion, the overlay layer had a defect that caused cracks. Based on these considerations, the inventors first determined the weight.
Cr5~15%, B0.05~1.5%, Si5~7%, Fe30%
We have developed a high-toughness Ni-based overlay alloy (hereinafter referred to as the "earlier invention alloy") consisting of 0.05 to 1.5% C, 5% W or less, and the balance substantially Ni, and have applied for a patent. (Japanese Patent Publication No. 59-35422) However, although the aforementioned invented alloy has dramatically improved toughness compared to conventional self-fluxing alloys, it cannot be used in high temperature ranges such as 700℃ to 900℃. As with conventional self-fluxing alloys, the alloy undergoes a softening phenomenon, making it practically impossible to use it in this temperature range. [Problems to be solved by the present invention] The present invention aims to solve the above-mentioned problems by:
Has toughness and heat resistance comparable to Co-based overlay alloys,
The object of the present invention is to provide a Ni-based overlay alloy that does not contain expensive elements and is also economically efficient. The present inventors conducted research on improving properties by adding various elements based on the previously invented alloy, and as a result,
It has been found that by containing Al within a predetermined range, hardness and impact strength are improved, and at the same time, heat resistance is also improved. [Means for solving the problem] The alloy of the present invention has (1) Cr5 to 15% by weight, B0.05 to
1.5%, Si5~7%, Fe20% or less, C0.05~1.5%,
A Ni-based high-toughness heat-resistant alloy for hardfacing, characterized in that it contains 0.5 to 5% of Al, and the remainder consists essentially of Ni. (2) Cr5~15%, B0.05~1.5%, Si5~ by weight
7%Fe20% or less, C0.05~1.5%, Al0.5~5%,
This is a Ni-based high-toughness heat-resistant alloy for hardfacing, characterized in that it contains 5% or less of W, and the remainder consists essentially of Ni. [Function] Next, the reason for limiting the content of the constituent elements of the alloy of the present invention will be described. Hereinafter, % indicates weight %. Al0.5~5.0% Al is the most important element in this invention.
When Al is contained in the range of 0.5%, both hardness and impact strength are improved, and when Al is contained in 2%, both hardness and impact strength reach their maximum values. Al contained in the alloy of the present invention enters the Ni solid solution forming the matrix of the alloy, forms an intermetallic compound represented by Ni ₃ Al, and strengthens the alloy. When the Al content is less than 0.5%, this effect disappears, and when it exceeds 5%, not only does the effect of the inclusion disappear, but it also has a negative effect on overlay weldability. For the above reasons, the Al content was limited to 0.5 to 5%. Cr5-15% Cr is an essential element for maintaining heat resistance and corrosion resistance. For this purpose, a minimum content of 5% is required, but if the Cr content exceeds 15%, an intermetallic compound will be formed between B and C, and the toughness of the alloy will decrease. For the above reasons, the Cr content was limited to 5 to 15%. B0.05~0.5%/Si5~7% Both B and Si form a highly hard intermetallic compound, precipitate in the alloy, and have the function of improving the hardness of the alloy and the build-up properties. . B0.05
% or less, Si5% or less, the hardness becomes HC35 or less, and a large amount of slag without self-flux is generated during overlay, impairing overlay weldability. Also B1.5%
Above, when the Si content exceeds 7%, the toughness of the alloy decreases. For the above reasons, the content of B and Si is B0.05~1.5
%, and Si was limited to 5 to 7%. Fe 20% or less Fe is an element in the same group as Ni, and it is also cheaper than Ni, so from an economic standpoint, it is preferable to include as much as possible as a substitute element for Ni. However, if the Fe content exceeds 20%, the alloy hardness decreases. For the above reasons, the Fe content was limited to 20% or less. C0.05~1.5% C has the function of improving the hardness of the alloy, but
When the C content is 0.05% or less, the hardness decreases,
Moreover, when it exceeds 1.5%, the toughness of the alloy decreases. For the above reasons, the C content was limited to 0.05 to 1.5%. W 5% or less W is dispersed in the matrix of the alloy and has the function of improving hardness and heat resistance, but when the W content exceeds 5%, the toughness of the alloy decreases. For the above reasons, the W content was limited to 5% or less. [Example] Next, as an example based on the present invention, the results of an experiment using an alloy of the present invention manufactured with a composition within the scope of the claims and an alloy of a comparative example will be described. Table 1 shows the composition, hardness (cast material hardness), and impact strength of the alloys of the present invention (11 types) and the alloys of comparative examples (3 types).

【表】【table】

〔Effect of the invention〕

以上、詳述したように、本発明の合金は、700
℃〜900℃といつた高温域での使用において、優
れた耐熱性を示し、かつ材料費における経済的有
利性も有する。 As detailed above, the alloy of the present invention has 700
It exhibits excellent heat resistance when used in a high temperature range of .degree. C. to 900.degree. C., and is also economically advantageous in terms of material costs.

[Brief explanation of the drawing]

第１図は、本発明の合金と比較例の合金の800
℃における恒温加熱後の硬さ、衝撃強さの変化、
第２図は、本発明の合金と比較例の合金のTIG肉
盛層の900℃における恒温加熱後の硬さの変化を
示したものである。 Figure 1 shows 800% of the alloy of the present invention and the alloy of the comparative example.
Changes in hardness and impact strength after constant temperature heating at °C,
FIG. 2 shows the change in hardness of the TIG overlay layer of the alloy of the present invention and the alloy of the comparative example after constant temperature heating at 900°C.

Claims

[Claims] 1. Cr5-15%, B0.05-1.5%, Si5-7% by weight
A Ni-based high-toughness heat-resistant alloy for hardfacing, characterized in that it contains 20% or less of Fe, 0.05 to 1.5% of C, and 0.5 to 5% of Al, with the balance essentially consisting of Ni. 2 Cr5-15%, B0.05-1.5%, Si5-7% by weight
Fe20% or less, C0.05-1.5%, Al0.5-5%, W5%
A Ni-based high-toughness heat-resistant alloy for hardfacing, characterized in that it contains the following, with the remainder essentially consisting of Ni.