JPH0461054B2 - - Google Patents
Info
- Publication number
- JPH0461054B2 JPH0461054B2 JP31743987A JP31743987A JPH0461054B2 JP H0461054 B2 JPH0461054 B2 JP H0461054B2 JP 31743987 A JP31743987 A JP 31743987A JP 31743987 A JP31743987 A JP 31743987A JP H0461054 B2 JPH0461054 B2 JP H0461054B2
- Authority
- JP
- Japan
- Prior art keywords
- mold
- electron beam
- melting
- titanium
- shell
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000010894 electron beam technology Methods 0.000 claims description 36
- 238000002844 melting Methods 0.000 claims description 17
- 230000008018 melting Effects 0.000 claims description 17
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 14
- 239000010936 titanium Substances 0.000 claims description 14
- 229910052719 titanium Inorganic materials 0.000 claims description 14
- 238000005266 casting Methods 0.000 claims description 9
- 230000001678 irradiating effect Effects 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 3
- 230000007547 defect Effects 0.000 description 15
- 230000007423 decrease Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000007711 solidification Methods 0.000 description 4
- 230000008023 solidification Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000003746 surface roughness Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 230000000740 bleeding effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000012768 molten material Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000000700 radioactive tracer Substances 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Landscapes
- Manufacture And Refinement Of Metals (AREA)
Description
〔産業上の利用分野〕
本発明は電子ビーム再溶解炉(EBR)を用い
てチタンを溶解・精練しインゴツトを製造する
際、インゴツト表面欠陥を防止することにより表
面研削を省略し歩留の向上を可能とする技術に関
するものである。
〔従来の技術〕
現在、チタンのインゴツト製造の主流は真空ア
ーク溶解炉(VAR)である。VARはアークを熱
源として用いるため、その安定性を確保する必要
があり丸断面のインゴツトしか製造することがで
きない。一方、EBRでは電子ビーム(EB)の偏
向制御が容易に可能であることから丸ばかりでな
く矩形等種々の断面形状を持つインゴツトを製造
することができる。
EBRの操業は以下の様に行われる。EBは溶解
室に送り込まれる溶解材料に照射させ材料を溶解
すると同時に鋳型内の溶融プール表面に照射され
ブールの形成・維持に用いられる。鋳型等への抜
熱により凝固が進行し、凝固した量だけインゴツ
トは下方へ引き抜かれる。
従来、EBR溶解条件としてはSiegfried
Schiller、Ullrich Heisig、Siegfied Panzer著
ELECTRON BEAM TECHNOLOGY(JOHN
WILEY & SONSInc.1982)に若干の記述が
ある。すなわち、同著262ページの表4.1にチタン
1Kgを溶解するために必要な総電力量である比電
力消費量は2〜5KWHr/Kgと示されている。ま
た、269ページの図4.12にインゴツトの直径とEB
出力の関係が示されている。しかしながら、これ
らの条件はチタンの溶解作業を行う上での目安を
与えるのみであり、インゴツト表面欠陥を防止す
る条件とはなつておらず、またEBRの最大の特
徴である種々の断面形状を持つインゴツトを製造
し美麗な表面肌を得る条件は提示されていない。
〔発明が解決しようとする問題点〕
本発明はかかる事情に着眼してなされたもので
ある。すなわち、EBRにおいて種々の断面形状
を持つインゴツトを製造する場合、インゴツト断
面形状、鋳造速度、EB出力およびEBの照射パタ
ーンを最適化しないと表面欠陥が多発し、欠陥を
除去するため通常5〜7mm表面研削が必要となり
歩留が低下する。
本発明は、インゴツトの表面欠陥の発生を防止
して表面研削量を低減し、歩留の高いEBR溶解
技術を確立することを目的とするものである。
〔問題点を解決するための手段、作用〕
本発明の方法は、チタンの電子ビーム溶解にお
いて、電子ビーム出力E(KW)、鋳型断面積S
(cm2)、鋳造速度V(Kg/Hr)を、0.1×S≦V≦
0.4×Sおよび
0.06×S+0.5×V+40<E<0.06×S
+1.0×V+110
の条件に設定し、かつ電子ビームの鋳型内の照射
中心を鋳型壁から40mm以内に置き照射しつつ溶解
を行うことを特徴とする。
EBRで従来の条件により製造されたインゴツ
トの表面欠陥を第1図に示す。第1図では各種欠
陥の断面形状を示しているが、欠陥としては鋳型
内未充満肌、二重肌および横割れがある。以下そ
れら欠陥の発生原因を述べる。
鋳型内未重満肌は、EB入熱量が鋳型による伝
導伝熱あるいは鋳型内溶融プール表面からの輻射
伝熱等インゴツト形状に依存する抜熱量と較べ低
く、冷却速度が速い場合、溶融チタン(湯)が鋳
型内に完全に充満する前に凝固が完了することに
より発生する。
二重肌の発生原因は二通りある。第一は、凝固
シエルと鋳型内壁の間にシエルの凝固収縮あるい
はインゴツト引抜時の振動等により形成された間
隙に湯が侵入し、シエル強度が低い場合、シエル
の溶融プール側への内傾変形が惹起され、さらに
湯が間隙内にオーバーフローすることにより二重
肌が発生する。また、鋳造速度が高い場合、溶融
プール面の揺動が激しくなりオーバーフローが助
長される。第二は、シエル強度が低い場合、鋳型
内壁とシエルとの摩擦力によりシエルが破断しそ
の破断部より湯が流出する所謂ブリーデイング現
象により二重肌が発生する。いずれにせよ、シエ
ル強度が低い場合に二重肌が発生する。チタンの
融点直下における引張強度は低いので、シエルを
厚く形成し応力を低減する必要がある。
第2図に、305×61mmの鋳型を用い、溶解中に
溶融プールにトレーサーとしてニツケルを添加
し、インゴツト断面観察により求めた凝固シエル
の傾きと二重肌を表面粗度で評価した結果を示
す。シエルの傾きが大きくなるほど、即ち凝固初
期よりシエルが厚く生成するほど表面素度は減少
し、前述したシエルに作用する応力緩和により二
重肌の発生は低減されることが判る。
シエル形状は溶融プールへの総EB入熱量ある
いはEBの照射パターンによるプールの局所的加
熱等により制御される。鋳型内におけるEB照射
中心を鋳型壁から離して照射すると、シエルの傾
きが減少し二重肌が多発する。EB照射中心と鋳
型内壁の距離が40mmを超えると極端に二重肌が発
生し、インゴツト表面研削量は3mm以上となり、
歩留が低下する。なお、EB出力が増加すると二
重肌は多発する。
第3図は、157mm角のビレツトを溶解した場合
の、EB出力と横割れ発生長さを示す図であるが、
EB出力を減少すると横割れは増加する。これは、
鋳型内でインゴツト表面温度が、チタンの延性が
低下する変態温度近傍まで低下し、摩擦力あるい
は引き抜きに伴う振動に起因する引張・曲げ応力
により横割れが発生するためと考えられる。この
ような横割れが発生する状態は、EB出力、鋳型
形状等に依存する抜熱および鋳造速度により制御
される。
鋳型形状の影響を調査するため、その断面が角
丸、矩形の鋳型を用い、鋳型内溶融プールを形
成・維持できるEB出力を調査した。輻射による
抜熱の影響が大きいためと考えられるが、EB出
力は鋳型断面積に比例し、鋳型形状の影響は鋳型
面積で評価できることが判つた。
本発明はかかる知見に基づきなされたものであ
り、上述した表面欠陥発生に影響を与えるEB出
力、鋳型形状、鋳造速度及びEB照射方法を最適
化することによつて欠陥発生を防止するものであ
る。
表面欠陥を防止し得る条件は以下の通りであ
る。チタンの電子ビーム溶解において、電子ビー
ム出力E(KW)、鋳型断面積S(cm2)、鋳造速度V
(Kg/Hr)を、0.1×S≦V≦0.4×Sおよび
0.06×S+0.5×V+40<E<0.06×S
+1.0×V+110
の条件に設定し、かつ電子ビームの鋳型内の照射
中心を鋳型壁から40mm以内に置き照射しつつ溶解
を行う。
第4図は、断面積250cm2の鋳型を用いて角ビレ
ツトを製造した場合の本発明条件とビレツトの表
面研削量との関係を示す図である。なお、EBの
鋳型内の照射中心は、鋳型内壁より20mmに置き照
射した。E=0.06×S+0.5×V+40の直線以下
では、横割れ及び型内未充満肌が、またE=0.06
×S+1.0×V+110の直線以上では二重肌が多発
し、表面欠陥を無くすためには1mmを越える研削
量が必要である。一方、Vが0.4×Sより大きな
場合は、二重肌が発生し研削量が増加する。Vが
0.1×Sより小さな場合は、生産能率上実用的で
はないばかりでなく横割れが多発する。なお、
EB照射中心が鋳型内壁より40mmを越えた位置に
照射されると1mmを越える表面研削量が必要とな
る。
〔実施例〕
第1表に実施例を示す。第1表No.1〜No.4まで
は本発明例であり、No.5〜No.8は比較例である。
表中には参考のため本発明の最適条件限界を併せ
て示している。No.1〜No.4では、種々の鋳型形状
にも関わらず、本発明条件範囲内であれば表面研
削量は比較例と較べて著しく少ない。No.5、6は
電子ビーム出力を本発明の最適条件限界よりそれ
ぞれ高くおよび低く設定し溶解を行つた例である
が、いずれも表面欠陥を除去するための表面研削
量が多くなつている。No.7は鋳型断面積で規定さ
れる鋳造速度より高い速度で鋳造した例である
が、二重肌が多発し表面研削量が多くなつてい
る。No.8は、電子ビーム照射位置が本発明条件よ
りはずれて溶解された例であるが、他の条件が適
切でも表面研削量は多くなつている。
[Industrial Application Field] The present invention improves yield by omitting surface grinding by preventing ingot surface defects when manufacturing ingots by melting and refining titanium using an electron beam remelting furnace (EBR). It is related to the technology that makes it possible. [Prior Art] Currently, the mainstream method for producing titanium ingots is a vacuum arc melting furnace (VAR). Since VAR uses an arc as a heat source, its stability must be ensured and it is only possible to produce ingots with a round cross section. On the other hand, in EBR, since the deflection of the electron beam (EB) can be easily controlled, ingots with various cross-sectional shapes such as not only round but also rectangular shapes can be manufactured. EBR operations are carried out as follows. EB is used to irradiate the molten material fed into the melting chamber to melt the material, and at the same time irradiates the surface of the molten pool in the mold to form and maintain the boule. Solidification progresses as heat is removed from the mold, and the ingot is pulled downward by the solidified amount. Traditionally, Siegfried is the EBR melting condition.
Written by Schiller, Ullrich Heisig, and Siegfied Panzer
ELECTRON BEAM TECHNOLOGY (JOHN
WILEY & SONSI Inc.1982) has some descriptions. That is, Table 4.1 on page 262 of the same book shows that the specific power consumption, which is the total amount of power required to melt 1 kg of titanium, is 2 to 5 KWHr/Kg. Also, Figure 4.12 on page 269 shows the ingot diameter and EB.
Output relationships are shown. However, these conditions only provide a guideline for performing titanium melting work, and do not provide conditions for preventing ingot surface defects, and the ingot has various cross-sectional shapes, which is the most distinctive feature of EBR. The conditions for producing ingots and obtaining beautiful surface skin are not presented. [Problems to be Solved by the Invention] The present invention has been made with attention to such circumstances. In other words, when manufacturing ingots with various cross-sectional shapes using EBR, surface defects occur frequently unless the ingot cross-sectional shape, casting speed, EB output, and EB irradiation pattern are optimized. Surface grinding is required, which reduces yield. The purpose of the present invention is to prevent the occurrence of surface defects in ingots, reduce the amount of surface grinding, and establish an EBR melting technology with a high yield. [Means and effects for solving the problem] The method of the present invention is applicable to the electron beam melting of titanium by reducing the electron beam power E (KW) and mold cross-sectional area S.
(cm 2 ), casting speed V (Kg/Hr), 0.1×S≦V≦
The conditions were set to 0.4 x S and 0.06 x S + 0.5 x V + 40 < E < 0.06 x S + 1.0 x V + 110, and the irradiation center of the electron beam in the mold was placed within 40 mm from the mold wall to melt while irradiating. It is characterized by doing. Figure 1 shows the surface defects of ingots produced using EBR under conventional conditions. FIG. 1 shows the cross-sectional shapes of various defects, and the defects include unfilled skin in the mold, double skin, and transverse cracks. The causes of these defects will be described below. If the EB heat input is lower than the amount of heat removed depending on the shape of the ingot, such as conductive heat transfer through the mold or radiation heat transfer from the surface of the molten pool in the mold, and the cooling rate is fast, the molten titanium (molten titanium) This occurs because solidification is completed before the mold is completely filled. There are two causes of double skin. First, if hot water enters the gap formed between the solidified shell and the inner wall of the mold due to solidification shrinkage of the shell or vibration during pulling out of the ingot, and if the strength of the shell is low, the shell will be deformed inward toward the molten pool. is caused, and hot water overflows into the gap, resulting in double skin. Furthermore, when the casting speed is high, the molten pool surface vibrates violently, promoting overflow. Second, when the shell strength is low, double skin occurs due to the so-called bleeding phenomenon in which the shell breaks due to the frictional force between the inner wall of the mold and the shell, and hot water flows out from the broken part. In any case, double skin occurs when the shell strength is low. Since the tensile strength of titanium is low just below its melting point, it is necessary to form a thick shell to reduce stress. Figure 2 shows the results of evaluating the inclination of the solidified shell and double skin by surface roughness, which were determined by observing the ingot cross section, using a 305 x 61 mm mold and adding nickel as a tracer to the molten pool during melting. . It can be seen that the greater the inclination of the shell, that is, the thicker the shell is from the initial stage of solidification, the more the surface roughness decreases, and the occurrence of double skin is reduced due to the aforementioned stress relaxation acting on the shell. The shell shape is controlled by the total EB heat input to the molten pool or the local heating of the pool by the EB irradiation pattern. If the EB irradiation center in the mold is irradiated away from the mold wall, the inclination of the shell will decrease and double skin will occur frequently. If the distance between the center of EB irradiation and the inner wall of the mold exceeds 40 mm, double skin will occur extremely, and the amount of ingot surface grinding will be 3 mm or more.
Yield decreases. Note that double skin occurs frequently as EB output increases. Figure 3 is a diagram showing the EB output and the length at which horizontal cracks occur when a 157 mm square billet is melted.
Lateral cracking increases when the EB output is reduced. this is,
This is thought to be because the surface temperature of the ingot in the mold drops to near the transformation temperature, at which the ductility of titanium decreases, and transverse cracking occurs due to tensile and bending stress caused by frictional force or vibrations associated with drawing. The state in which such transverse cracks occur is controlled by heat removal and casting speed, which depend on EB output, mold shape, etc. In order to investigate the influence of mold shape, we used molds with rounded corners and rectangular cross sections, and investigated the EB output that can form and maintain a molten pool inside the mold. This is thought to be due to the large effect of heat removal due to radiation, but it was found that EB output is proportional to the cross-sectional area of the mold, and that the influence of mold shape can be evaluated by the mold area. The present invention was made based on this knowledge, and is intended to prevent the occurrence of defects by optimizing the EB output, mold shape, casting speed, and EB irradiation method that affect the occurrence of surface defects as described above. . Conditions that can prevent surface defects are as follows. In electron beam melting of titanium, electron beam power E (KW), mold cross-sectional area S (cm 2 ), casting speed V
(Kg/Hr) is set to the following conditions: 0.1×S≦V≦0.4×S and 0.06×S+0.5×V+40<E<0.06×S +1.0×V+110, and the irradiation center of the electron beam inside the mold Place it within 40mm from the mold wall and melt while irradiating it. FIG. 4 is a diagram showing the relationship between the conditions of the present invention and the amount of surface grinding of the billet when a square billet is manufactured using a mold with a cross-sectional area of 250 cm 2 . The irradiation center in the EB mold was placed 20 mm from the inner wall of the mold. Below the straight line of E = 0.06 x S + 0.5 x V + 40, horizontal cracks and unfilled skin within the mold occur, and E = 0.06
Double skin occurs frequently above the straight line ×S+1.0×V+110, and a grinding amount of more than 1 mm is required to eliminate surface defects. On the other hand, when V is larger than 0.4×S, double skin occurs and the amount of grinding increases. V is
If it is smaller than 0.1×S, it is not only impractical in terms of production efficiency, but also causes frequent horizontal cracks. In addition,
If the EB irradiation center is irradiated at a position more than 40mm from the mold inner wall, surface grinding amount of more than 1mm is required. [Example] Table 1 shows examples. Table 1 Nos. 1 to 4 are examples of the present invention, and Nos. 5 to 8 are comparative examples.
In the table, the optimum condition limits of the present invention are also shown for reference. In No. 1 to No. 4, despite the various mold shapes, the amount of surface grinding was significantly smaller than that of the comparative example as long as the conditions of the present invention were within the range. Nos. 5 and 6 are examples in which melting was performed by setting the electron beam output higher and lower than the optimal condition limit of the present invention, respectively, but in both cases the amount of surface grinding to remove surface defects was large. No. 7 is an example in which casting was performed at a speed higher than the casting speed specified by the cross-sectional area of the mold, but there were many double skins and a large amount of surface grinding. No. 8 is an example in which the electron beam irradiation position was deviated from the conditions of the present invention and melted, but even if the other conditions were appropriate, the amount of surface grinding was large.
本発明は以上のように構成されており、チタン
のEBR溶解を行う場合、種々の断面形状を持つ
インゴツトの表面欠陥を防止し、表面研削量を低
減することにより歩留の高いEBR溶解を可能と
するものである。
The present invention is configured as described above, and when performing EBR melting of titanium, it is possible to perform EBR melting with a high yield by preventing surface defects of ingots with various cross-sectional shapes and reducing the amount of surface grinding. That is.
第1図はEBR溶解インゴツトの表面欠陥を示
す図、第2図は凝固シエルの傾きとインゴツト表
面粗度の関係を示す図、第3図はEB出力と横割
れ発生長さの関係を示す図、第4図はその断面積
が250cm2の鋳型を用いEBR溶解を行つた場合本発
明の条件範囲と表面研削量の関係を示す図であ
る。
Figure 1 shows the surface defects of EBR melted ingots, Figure 2 shows the relationship between the inclination of the solidified shell and the ingot surface roughness, and Figure 3 shows the relationship between the EB output and the length at which transverse cracks occur. , FIG. 4 is a diagram showing the relationship between the condition range of the present invention and the amount of surface grinding when EBR melting is performed using a mold with a cross-sectional area of 250 cm 2 .
Claims (1)
ム出力E(KW)、鋳型断面積S(cm2)、鋳造速度V
(Kg/Hr)を、0.1×S≦V≦0.4×Sおよび 0.06×S+0.5×V+40<E<0.06×S +1.0×V+110 の条件に設定し、かつ電子ビームの鋳型内の照射
中心を鋳型壁から40mm以内に置き、照射しつつ溶
解を行うことを特徴とするチタンの電子ビーム溶
解方法。[Claims] 1. In electron beam melting of titanium, electron beam power E (KW), mold cross-sectional area S (cm 2 ), casting speed V
(Kg/Hr) is set to the following conditions: 0.1×S≦V≦0.4×S and 0.06×S+0.5×V+40<E<0.06×S +1.0×V+110, and the irradiation center of the electron beam inside the mold A titanium electron beam melting method characterized by placing titanium within 40 mm from the mold wall and melting while irradiating it.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP31743987A JPH01159334A (en) | 1987-12-17 | 1987-12-17 | Method of electron beam melting for titanium |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP31743987A JPH01159334A (en) | 1987-12-17 | 1987-12-17 | Method of electron beam melting for titanium |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH01159334A JPH01159334A (en) | 1989-06-22 |
JPH0461054B2 true JPH0461054B2 (en) | 1992-09-29 |
Family
ID=18088231
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP31743987A Granted JPH01159334A (en) | 1987-12-17 | 1987-12-17 | Method of electron beam melting for titanium |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH01159334A (en) |
-
1987
- 1987-12-17 JP JP31743987A patent/JPH01159334A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPH01159334A (en) | 1989-06-22 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN110280746B (en) | Method for single-source high-intensity ultrasonic-assisted casting of large-specification 2XXX series aluminum alloy round ingot | |
US8668760B2 (en) | Method for the production of a β-γ-TiAl base alloy | |
CN107164639B (en) | A kind of electron beam covers the method that formula solidification technology prepares high temperature alloy | |
US6561259B2 (en) | Method of melting titanium and other metals and alloys by plasma arc or electron beam | |
JP5315345B2 (en) | Silicon purification method | |
JP3646570B2 (en) | Silicon continuous casting method | |
CN103526038B (en) | A kind of high-strength high-plasticity TWIP steel esr production method | |
CN107385244B (en) | A kind of electron beam covers the method that induced coagulation technology High Purity prepares nickel base superalloy | |
KR101275218B1 (en) | Method for refining metal | |
JP5788691B2 (en) | Melting furnace for melting metal and method for melting metal using the same | |
CN107760877A (en) | The method of smelting of ingot casting | |
CN204589271U (en) | Electroslag furnace | |
CN109047685A (en) | A method of preparing steel ingot | |
JPH0461054B2 (en) | ||
CN110484742B (en) | Method for preparing Fe-W intermediate alloy by electron beam melting and high purification | |
KR20140129338A (en) | Mold for continuous casting of titanium or titanium alloy ingot, and continuous casting device provided with same | |
JP7135556B2 (en) | Method for manufacturing titanium ingot | |
JP4274872B2 (en) | Electron beam melting method for refractory metal materials | |
JP2020015973A (en) | Manufacturing method and manufacturing apparatus of titanium ingot or titanium alloy ingot | |
JP7406074B2 (en) | Titanium ingot manufacturing method and titanium ingot manufacturing mold | |
JPH0531568A (en) | Plasma melting/casting method | |
JPS61279638A (en) | Manufacture of ingot from metallic scrap | |
JPH0711352A (en) | Method for continuously melting and casting high melting point active metal | |
JP5022184B2 (en) | Ingot manufacturing method for TiAl-based alloy | |
RU2238992C1 (en) | Niobium ingot preparation method |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
LAPS | Cancellation because of no payment of annual fees |