A Study on the Development of Hot Rolling Process for 18Cr-10Mn-0.44N₂

DOI : 10.5228/KSTP.2011.20.4.296͑ G

Y`]GV穢剳暒昷儆击穟箒滆V洢YW劒G 洢[笾SGYWXX噊G

18Cr-10Mn-0.44N

G

卆欇姣¹ · 浶涋岞^# · 決涋殷²· 愶毖懗³ G

A Study on the Development of Hot Rolling Process for 18Cr-10Mn-0.44N

G

Y. D. Kim, J. R. Cho, J. W. Lee, W. B. Bae

(Received March 2, 2011 / Revised June 17, 2011 / Accepted June 21, 2011) G

Abstract

The objective of this paper is to determine the effect of process parameters on the behavior of a 18Cr-10Mn-0.44N₂ nitrogen steel sample deformed by hot rolling. Compression tests were carried out at high temperatures to determine the flow stresses needed for a finite element(FE) analysis. The strain rate, ranging from 0.1 to 1.0s^-1, significantly affected the flow stress at temperatures higher than 1,000^oC. Non-isothermal rolling simulations and laboratory rolling tests were performed with plate specimens 14.5mm thick, 135mm wide and 226mm long. A rolling reduction of 15% per pass leading to a cumulative rolling reduction of 60% was determined as optimal. The extension ratio of 176.5% in the length direction was about 30.4 times greater than the extension ratio of 5.8% in the width direction. Isotropic properties for tensile strength, microstructure and grain size were measured after mock-up hot rolling tests. The results from the mock- up tests were found to be in good agreement with those of the simulations.

G G

Key Words : HNS(High Nitrogen Steel), High Temperature Flow Stress Curve, Hot Rolling Process, FE Simulation, Cumulative Rolling Ratio, Microstructure, Pressurized Vacuum Induction Melting

41# ⇆# ᤊ# G

1930 ⎚╖ 㿲䡚䞲 㓺䎢㧎⩞㓺ṫ(SUS)㦖 ₆Ἒ㩗, ⶒⰂ㩗 ㎇㰞㧊 㤆㑮䞮ἶ 䔏䧞 㧚Ἒ ⌊㔳㎇ὒ ゚ 㧦㎇ 䔏㎇㦚 Ṗ㰖ἶ 㧞㠊 ㌆㠛㣿 ῂ㫆ⶒ ⹥ ṗ㫛

₆Ἒ⿖䛞 ❇㦮 㭒㣪 ㏢㨂⪲ ㌂㣿♮㠊 㢪┺[1]. ⁎

⩂⋮, 21 ㎎₆㠦 ✺㠊㍲Ⳋ㍲ 㰖ῂ ㎎Ἒ⓪ 䢮ἓ 䂲 䢪䡫 ㏢㨂⯒ 㣪ῂ䞮Ⳇ ▪ ⋮㞚Ṗ ₆㫊㦮 SUS ㏢ 㨂㦮 㩲⹮ 䔏㎇㦚 Ⱒ㫇䞾ὒ ☯㔲㠦 ἓ㩲㎇㦚 Ṭ 㿮 㔶㏢㨂⯒ 㭒ⶎ䞮ἶ 㧞┺. ₆㫊 SUS 㦮 㭒㣪 䞿

⁞㤦㏢㧎 Ni 㦖 䞲㩫♲ 㧦㤦㠦 ➆⯎ ἓ㩲㩗 ⿞Ⰲ 䞾ὒ 㧎㼊 㞢⧮⯊₆ 㥶⹲ ⹥ 㨂䢲㣿㔲 㥶䟊Ṗ㓺

⹿㿲㧊⧒⓪ ⶎ㩲㩦㦚 㞞ἶ 㧞┺. 㧊⯒ ╖㼊䞮ἶ㧦

Ni ╖㔶 ┺⨟㦮 㰞㏢⯒ 䞾㥶㔲䋾 ἶ㰞㏢ṫ(HNS, High Nitrogen Steel)㧊 ╖⚦♮ἶ 㧞┺. ἶ㰞㏢ṫ㧊

⧖ ╖₆㞫䞮㠦㍲ ἶ㣿䞲Ἒ 㧊㌗㦒⪲ 㰞㏢Ṗ 㻾Ṗ

♲ ṫ㦚 Ⱖ䞮Ⳇ 㡺㓺䎢⋮㧊䔎Ἒ㠦㍲ 㭧⨟゚ 0.4%

㧊㌗㦮 㰞㏢⯒ 䞾㥶䞲 ṫ㦚 㦮⹎䞲┺[2, 3]. 1988 ⎚ 䝚⧧㓺㠦㍲ 㩲 1 䣢 ῃ㩲䞯㑶䣢 Ṳ㾲⯒ 㔲㧧㦒⪲

㩦㹾 䢲⹲䞲 㡆ῂ䢲☯㧊 㧊⬾㠊㰖ἶ 㧞┺[4~9]. ῃ

⌊⓪ 㓺䎢㧎Ⰲ㓺ṫ㦮 䔏㎇䟻㌗㦚 ⳿㩗㦒⪲ 㰞㏢

㻾Ṗ⯒ 㔲☚䞲 㡆ῂṖ[10~13] 㧊⬾㠊㪎 㢪㰖Ⱒ ⽎ ỿ㩗㧎 ἶ㰞㏢ṫ㠦 ╖䞲 㡆ῂ⓪ 㔲㧧┾Ἒ⧒ ⽒ 㑮 㧞┺. 䞿⁞㍺Ἒ⯒ 䐋䟊 Ṳ⹲♲ ㏢㨂㠦 ╖䟊 ㏢

㎇ṖὋ ₆㑶㦚 㩧⳿䞲 㩲㫆Ὃ㩫 㡆ῂṖ 㧒⿖ 㧊

⬾㠊 㰖ἶ 㧞㦒⋮ 㥶䞲㣪㏢ ⁞㏣㎇䡫䟊㍳ ₆㑶⿚

XUG ⚦㌆㭧Ὃ㠛G ₆㑶㡆ῂ㤦G ㏢㨂₆㑶Ṳ⹲䕖G YUG ⚦㌆㭧Ὃ㠛G ₆㑶㡆ῂ㤦G ㏢㨂₆㑶Ṳ⹲䕖G ZUG ⿖㌆╖䞯ᾦG 㩫⹖₆ἚὋ䞯ὒG

JG ᾦ㔶㩖㧦aG 䞲ῃ䟊㟧╖䞯ᾦSGlT”ˆ“aGŠ‘™gœUˆŠU’™G

穢穢剳暒昷儆击穟箒滆V洢YW劒G 洢[笾SGYWXX噊VY`^G G 㟒⓪ 㞚㰗 ⹎⹎䞲 㑮㭖㧊┺[14~16].

➆⧒㍲, ⽎ 㡆ῂ㠦㍲⓪ 㩲㧧♲ 18Cr-10Mn-0.44N2

ἶ㰞㏢ṫ ㏢㨂㠦 ╖䟊 㡊Ṛ㎇䡫 䔏㎇㧎㧦㠦 ➆⯎

ἶ㡾㥶☯㦧⩻ 㔲䠮㦚 㑮䟟䞮㡂 ₆㽞 ⶒ㎇◆㧊䌖

⯒ ῂ㿫䞮ἶ 㡊Ṛ㞫㡆Ὃ㩫 FE 㔲⸂⩞㧊㎮㦚 㑮䟟 䞮㡂 㡊Ṛ㞫㡆 Ὃ㩫㧎㧦⯒ ☚㿲䞮㡖┺. ☚㿲♲ 㧎 㧦✺㦖 㞫㡆䞮㭧 350 䏺 ′⳾㦮 㔺䠮㔺  ′⳾ 㡊 㡆㍺゚⯒ ῂ㿫䞮㡂 ㎇䡫㎇ ⹥ 䡫㌗⼖䡫 䔏㎇ 䁷 Ⳋ㠦㍲ Mock-up test 䞮㡂 Ỗ㯳䞮㡖ἶ 㡊Ṛ㞫㡆 䤚 㞫㡆䛞㠦 ╖䟊 ⹎㎎㫆㰗 ㌗䌲⯒ ゚ᾦ, ⿚㍳ 䞮⸖

⪲㍲ 㾲㩗 㡊Ṛ㞫㡆 Ὃ㩫㦚 㩲㞞䞮㡖┺.

#

51# ∶⡖㍣⇛Ḯ⇇# ⎎㚂#

514# ∶⡖⣆⤚#

㏢㨂⓪ Ṗ㞫䡫 㰚Ὃ㥶☚㣿䟊(PVIM, Pressurized Vacuum Induction Melting)㠦 㦮䟊 100Kg 㰲Ⰲ VIM (Vertical Induction Melting) 㤦㭒䡫 ṫᾊ⯒ 㩲㫆䞮㡖

┺.

Fig. 1㦖 㥶☯Ṗ㡊 㣿䟊⻫㦒⪲ Ṗ㞫䡫 㥶☚㣿䟊 (PVIM) 㧻゚(a)㢖 㩲㫆♲ ṫᾊ ㌂㰚(b)㧊┺. ṫᾊ

㌂㧊㯞⓪ 㰗ἓ 180×₎㧊 460mm 㧊ἶ 㭧⨟㦖 㟓 100kg 㧊┺.

Table 1 㦖 ㌂㣿 ㏢㨂㦮 䢪䞯㎇⿚㦚 ⽊㡂 㭒ἶ 㧞┺. ELTRA ㌂(☛)㦮 ON-900 ⿚㍳₆⯒ 㧊㣿䞮㡂 䁷㩫䞲 㰞㏢ ⏣☚Ṩ㦖 㟓 4,450ppm, 2.0Ni ⪲㍲ 䐋

㌗㩗㧎 㓺䎢㧎Ⰲ㓺ṫ㦮 Ni 䞾⨟ 㟓 8~14% ₆㭖䞮 㡂[1] 䘟‶ 㟓 82% 㩫☚ ⌄㦖 㑮㭖㦚 ⽊㧎┺.

(a) PVIM equipment (b) Ingot Fig. 1 Photograph of PVIM equipment and VIM

ingot with weight of 100kg

Table 1 Chemical composition of the HNS alloy (wt.%) C Si Mn Cr Ni Cu N(ppm) 0.024 0.4 10.0 18 2.0 1.01 4450

Fig. 2 Stress-strain curve according to strain rate(H =s^-1) at temperature 800^oC, 1,000^oC and 1,200^oC

515# ඊ⛒⟊ᒃ# ᯦⇛⎎㚂#

ἶ㡾㠦㍲㦮 ㏢㨂㥶☯䔏㎇⿚㍳㦚 㥚䞮㡂 㩲㫆䞲 VIM ṫᾊ 㭧㕂㠦㍲ ⳾㨂⯒ 㺚䀾䞲 䤚 㞫㿫㣿 㤦 㭒㔲䘎 㰗ἓ 8×⏨㧊 12(mm)⪲ ṖὋ䞮㡖┺. 㔲䠮㍺

゚⓪ HDS(Hot Deformation Simulator, Model:

Thermecmaster_Z10)㠦㍲ 㑮䟟♮㠞┺. 㔲䠮㫆Ị㦖 㡾☚ῂṚ 800^oC㠦㍲ 1,200^oC ₢㰖 100^oC Ṛỿ㦒⪲

⼖䡫㥾㏣☚(H)⓪ 0.1, 0.5, 1.0, 5.0, 10.0 㠦 㞫䞮㥾㦖 䘟‶ 50% ⳿䚲⪲ 㑮䟟䞮㡖┺.

Fig. 2 ⓪ 㔲䠮㡾☚ ῂṚ ⌊㠦㍲ ╖䚲㡾☚⯒ ㍶ 㩫䞮㡂 ⼖䡫㥾㠦 ➆⯎ 㦧⩻-⼖䡫㥾 Ệ☯㔲䠮㦚 䐋 䞮㡂 㠑㠊㰚 ㍶☚㧊┺. 㡗䟻 㧎㧦✺ 㭧 㡾☚㠦 㦮 䞲 㡗䟻㧊 Ṗ㧻 䋂Ⳇ ㌗╖㩗㦒⪲ ⌄㦖 㡾☚㧎 800^oC ⿖⁒㠦㍲⓪ ⼖䡫㥾㏣☚(H^{, s-1)㦮 㡗䟻㧊 㧧} 㰖Ⱒ 㡾☚Ṗ ⏨㦖 1,000^oC, 1,200^oC 㠦㍲⓪ ⼖䡫㥾

㏣☚Ṗ 㯳Ṗ䞾㠦 ➆⧒ 㦧⩻㧊 㯳Ṗ䞮⓪ ἓ䟻㦚

⽊㧊ἶ 㧞┺. ⡦䞲, ⌄㦖 ⼖䡫㥾㏣☚ ῂṚ 㧎 0.1~0.5(1.0)㠦㍲⓪ 㡗䟻㧊 䋂Ợ ⋮䌖⋮Ⳇ ⼖䡫㥾㏣

☚ 5.0 㧊㌗㠦㍲⓪ 㦧⩻⼖䢪㦮 䙃㧊 ⹎㏢䞾㦚 ⽊㧎

┺. 㧊⩂䞲 ἆὒ⓪ ἶ㡾 ⼖䡫㠦㍲ ⼖䡫㏣☚⯒ 㧚 㦮 ⻪㥚 ⌊㠦㍲ 䋂Ợ 䞮㡂☚ 䞮㭧㦮 㯳Ṗ䡚㌗㧊

⹎㏢䞮┺⓪ ộ㦚 㦮⹎䞲┺.

#

61# ⚞⚚ඟ⢿# ⎆᱖ᢲ⠞∂#

614# 㘞⇇⤚ഞ#

Fig. 3㦖 㡊Ṛ 㞫㡆䟊㍳㦚 㥚䞲 2-⪺ 䌖㧛㦮 3㹾

ڋ ڐڋ ڌڋڋ ڌڐڋ ڍڋڋ ڍڐڋ ڎڋڋ ڎڐڋ ڏڋڋ ڏڐڋ ڐڋڋ

ڋډڋ ڋډڌ ڋډڍ ڋډڎ ڋډڏ ڋډڐ

گۍېۀٻێۏۍڼۄۉ

گۍېۀٻێۏۍۀێێڃڨګڼڄ

_WW^–jG

XSWWW^–jG

XSYWW^–jG

Y

Y`_GV穢剳暒昷儆击穟箒滆V洢YW劒G 洢[笾SGYWXX噊G Fig. 3 Schematic modeling for hot rolling system

Table 2 Initial condition of roll and preform for hot rolling analysis (Size unit: mm)

Roll Preform

Dia.

I Width Bo

Temp.

( ^oC)

Width Wo

Thick.

to

Length Lo

Temp.

( ^oC) 320 250 25 134 14.5 217 1,250

㤦 ⳾◎䡫㌗㧊┺. ῂ☯⪺㦮 ῂ☯ὒ ☯㔲㠦 㰚㿲㧛ῂ

⽊㫆⪺㧊 䞾℮ 䣢㩚䞮Ⳋ㍲ 㞫㡆♮⓪ ῂ㫆㧊┺. 㽞₆

⪺㏣☚ 105mm/s, Ⱎ㺆Ἒ㑮 0.7㠦 ⪺, 䝚Ⰲ䙒 ㏢㨂

⹥ ╖₆Ṛ㦮 㡊㩚╂ ἶ⩺⓪ 䝚⪲⁎⧾㠦㍲ 㩲Ὃ䞮⓪ Ἒ㑮Ṩ㦚 ㌂㣿䞮㡖┺. 㡊㩚╂Ἒ㑮⓪ 50W/m²˜K㧊ἶ Emissivity⓪ 0.25㧊┺. 3-D 䡫㌗⳾◎ 䝚Ⰲ䙒㏢㨂㦮

⌊䁷(2t/3, t:㏢㨂⚦℮)㦖 FVM, 䚲Ⳋ⿖(t/3)⓪ FE₆⻫

㩗㣿㧊 Ṗ⓻䞲 ㏢㎇㩚㣿䟊㍳ 䝚⪲⁎⧾㧎 Simufact.

forming-8.1㞫㡆⳾✞㦚 ㌂㣿䞮㡖┺. 㔺㩲 ㌂㣿㍺゚

㦮 ⽊㫆⪺ 㡃䞶㦚 ⵮㌂䞮₆ 㥚䟊 㰚㧛ῂ ⹥ 㰚㿲 ῂ 䁷㦮 ⽊㫆⪺ ῂ☯㦚 ἶ⩺䞮㡖┺.

Table 2⓪ 㡊Ṛ㞫㡆 䟊㍳㦚 㥚䞲 ⪺ὒ 䕦㨂 䝚Ⰲ 䙒㦮 㽞₆㫆Ị㧊┺. 㾲㫛 㞫㡆 䤚 㞫㡆㨂㦮 ⳿䚲

⚦℮⓪ 4.0mm㧊┺.

#

61#5# 㘞⇇൚ඦ#

Fig. 4⓪ 1-Pass 㞫㡆㔲 㔺㩲 㑲Ṛ㞫㡆㥾(ARR%=

((t_i-t_i+1)/t_i)x100, t_i-t_i+1=t_f, i=1,2,~n)㠦 ➆⯎ ⼖䡫㟧㌗㦚 㫆㌂䞮㡖┺. 10~15%₢㰖⓪ 䙃, ⚦℮ ⹥ ₎㧊⹿䟻 㦮 㑮䘟☚Ṗ ⳾⚦ 㟧䢎䞲 ⼖䡫㌗䌲⯒ ⽊㧎┺. ⁎

⩂⋮ 20%㠦㍲ ⿖䎆⓪ 䕦⊳┾ 㧊㌗⼖䡫ὒ ₎㧊⹿

䟻 㑮䘟☚㠦㍲ 㧊㌗⼖䡫㧊 ⹲㌳䞲┺. 30% 㞫㡆 㔲

(a) Initial preform

(10%) (15%)

(10%) (15%) (b) 1-pass rolling

Fig. 4 State of deformation according to rolling reduction ratio(RR%) per one-pass rolling

㩚䤚Ⳋ ⊳┾ ゚⼖䡫ὒ 㑮䘟☚Ṗ 㕂䞲 䕦㨂䥾(G) ⶎ㩲Ṗ ⹲㌳䞲┺. ➆⧒㍲ 㧧㠛㎇ὒ 㞞㩫㩗㧎 ⼖䡫 㥶☚⯒ 㥚䞲 㽞₆ 㩗㩫 㞫㡆㥾㦖 㟓 15%⪲ ㍶㩫 䞶 㑮 㧞┺.

Fig. 5⓪ 1-Pass, 㞫㡆㥾(ARR%) 15%㠦㍲ 㞫㡆Ὃ 㩫 㰚䟟㠦 ➆⧒ 㥶䣾⼖䡫㥾 ⹥ 㡾☚⿚䙂 ⼖䢪⯒

㌊䘊 ⽊㞮┺. 㽞₆ 㰚㧛䞮㡂 㾲㫛㞫㡆 䤚 㰚㧛⿖

㢖 㧧㠛㧊 ⊳⋮⓪ ⊳┾⿖㠦㍲ ⼖䡫㥾 ⹥ 㡾☚⿚

䙂 㹾㧊Ṗ ⹲㌳䞲┺. ⼖䡫㥾 ⹥ 㡾☚⿚䙂 ㌗䌲⓪

㌗╖㩗㦒⪲ ⊳┾⿖㠦㍲ 䋂Ợ ⋮䌖⋮ἶ 㧞┺. 㧊⩂

䞲 ἆὒ✺㦖 ⼖䡫㧊 ⑚㩗 ♶ ἓ㤆 䕦㨂ↂ㧚, 䥮㧚, 㭒⯚ ❇㦮 ⶎ㩲⹲㌳ὒ 㧊㌗⼖䡫 Ṗ⓻㎇㧊 䄺㰞 㑮 㧞㦢㦚 㩲㔲䞲┺. ➆⧒㍲ 㩗㩞䞲 㞫㡆㥾ὒ 㨂 Ṗ㡊㠦 ╖䞲 Ὃ㩫㍺Ἒ, ⿚㍳㧊 䞚㣪䞮┺.

㽞₆ 䝚Ⰲ䙒⚦℮ to=14.5mm㠦㍲ ⑚㩗㞫㡆㥾(CRR%

=(t_o-t_f)/t_ox100) 㾲╖ 75% 㯟, 㾲㫛⚦℮ tf=3.6mm₢

㰖㧊ἶ, 㑲Ṛ㞫㡆㥾(ARR%)㦖 ṗ Ὃ㩫 ┾Ἒ ῆ㠦

㍲ 㑮⻞㦮 㞫㡆 䟊㍳ 㔲䠮㦚 䐋䟊 㾲㩗 Ṗ⓻ 㞫㡆 㥾㦚 ㍶㩫䞮㡖┺. 㞫㡆䟊㍳ 㭧 ㏢㨂㡾☚Ṗ 850^oC

₆㭖 㧊䞮⪲ ⟾㠊㰖Ⳋ 1250^oC ₢㰖 㔲Ṛ╏ 70^oC㦮 㔏㡾㏣☚⪲ 㨂Ṗ㡊 䤚 㡊㡆Ὃ㩫㦚 㑮䟟䞮㡖㦒Ⳇ Table 3㠦 㩫Ⰲ♮㠊 㧞┺.

Fig. 6㦖 ⑚㩗㞫㡆㥾(CRR%)=70%₢㰖 㯳Ṗ䟊 Ṗ Ⳋ㍲ Table 3 㦮 Rolling process Ὃ㩫 㭧 ṗ ┾Ἒ㠦 tˆ•GrollG

Forward Support roll Way-out partG Entry part

Backward Support roll

PreformG

穢穢剳暒昷儆击穟箒滆V洢YW劒G 洢[笾SGYWXX噊VY``G G

›G ›RXG

(Strain) (Temperature)

Fig. 5 Variation of effective strain and temperature according to 1-pass rolling advancing with RR=15%

Table 3 Rolling process for hot rolling Process Step1~4 Step5~8 Step9~10 Step11~12 Heating

No. 1-heat 2-heat 3-heat 4-heat CRR(%) 41 65 71 75 ARR(%) 15 13 7 5

㍲ ㍶㩫䞮㡂 䕦㨂㦮 ⼖䡫 ⹥ ㏢㨂Ệ☯䡫㌗㦚 ㌊ 䘊⽊㞮┺. CRR=50%₢㰖⓪ ₎㧊 ⹥ 䙃⹿䟻㠦㍲ ゚ ᾦ㩗 㟧䢎䞲 ⼖䡫㟧㌗㦚 ⽊㧊㰖Ⱒ ⑚㩗㞫㡆㥾 62%⿖䎆⓪ 䚲㔲䞲 㤦䡫㩦㍶㠦㍲㢖 ṯ㧊 ⊳┾⿖㠦

㍲㦮 ⿞‶㧒⼖䡫, ₎㧊⹿䟻㦒⪲㦮 㑮䘟☚ ⿞⨟㧊

⹲㌳䞮₆ 㔲㧧䞲┺. 70%⿖䎆⓪ ₎㧊⹿䟻 㩚Ⳋ㠦 Ỏ㼦 ⚦℮⼖䡫 ⿞‶㧒ὒ 䥾 䡚㌗㧊 ὒ☚䞮Ợ ⋮ 䌖⋲┺. ➆⧒㍲, ⽎ ㏢㨂㦮 ἓ㤆 㩗㩞䞲 㾲╖Ṗ⓻ 㞫㡆㥾㦖 㟓 60%⪲ ⿚㍳♲┺.

Fig. 7 㦖 㞫㡆㥾㯳Ṗ㠦 ➆⯎ 㞫㡆䕦㨂㦮 ₎㧊⹿

䟻 㔶㧻㥾(LR%=Lf/L_ox100)㢖 䙃⹿䟻 㔶㧻㥾(WR%=

Wf/Wox100) Ệ☯㦚 㫆㌂䞮㡖┺. ⑚㩗㞫㡆㥾(CRR%) 㧊 㯳Ṗ䞾㠦 ➆⧒ 㔶㧻゚⓪ 㯳Ṗ䞮㰖Ⱒ LR%Ṗ

㌗╖㩗㦒⪲ 䋂Ⳇ WR%⓪ 㾲㫛Ὃ㩫₢㰖 䋆 ⼖䢪Ṗ

(15%) (50%)

(23%) (62%)

(35%) (65%)

(41%) (70%)

Fig. 6 Behavior of plate deformation according to increasing of cumulative rolling ratio(CRR%)

Fig. 7 Behavior of length & width direction extension ratio(LR% & WR%) according to rolling reduction ratio

㠜┺. LR%⓪ 㞫㡆㥾 㟓 40%₢㰖⓪ 㧒㩫゚⪲ 㯳Ṗ 䞮Ⳇ 67%₢㰖 㫖 ▪ ザ⯎ 㯳Ṗ⯒ ⽊㧊┺Ṗ 70%

㧊䤚  ỿ䞲 㔶㧻㥾 㯳ṖṖ ⹲㌳䞲┺. LR%⓪ 㾲

╖ 176.5%, WR%⓪ 㾲╖ 5.8%⪲㍲ 㟓 30.4 ⺆ LR%

Ṗ 䋂┺. 㧊⩂䞲 ⼖䡫Ệ☯㦖 䣾㥾㩗㧎 㞫㡆䛞 ㌳

㌆㠦 㥶Ⰲ䞲 Ὃ㩫䣾ὒ⯒ 㩲Ὃ䞲┺.

Fig. 8 㦖 4 䣢 Ṗ㡊㠦㍲ 㑮䟟䞲 㞫㡆㥾 ṗ ┾Ἒ 㠦㍲ 㞫㡆 䕦㨂Ⳋ㦮 ₎㧊⹿䟻(x)ὒ 䙃⹿䟻(y)㦒⪲

㥚䂮⼚ 㥶䣾⼖䡫㥾 ㌗䌲⯒ 㫆㌂䞮㡖┺. Ṗ㡊䣢㑮

Z

ZWWGV穢剳暒昷儆击穟箒滆V洢YW劒G 洢[笾SGYWXX噊G ssG {kXG{kYG G {kZG{k[G G{k\G G

Entry Way-out

jsG

|sG

Fig. 8 Effective strain at thickness direction with rolling ratio(CRR%) & heating number

Fig. 9 Behavior of length & width direction extension ratio(LR% & WR%) according to rolling reduction ratio

Ṗ 㯳Ṗ䞮Ⳋ㍲ 㩞╖ 㥶䣾⼖䡫㥾㦮 Ṩ㦖 㧧㞚㰖ἶ 㧞┺. 㧊⓪ Ṗ㡊⪲ 㧎䟊 ㏢㨂 ⌊⿖⼖䡫㥾㧊 㽞₆ 䢪 ♮ἶ 䤚Ὃ㩫㦒⪲ Ṟ㑮⪳ 1 䣢╏ 㞫㡆⨟㧊 㧧㞚 㰖Ⳋ㍲ ⋮䌖⋮⓪ 䡚㌗㧊┺. 1-HT-41%㠦㍲ ⼖䡫㥾

⿚䙂⓪ 㞫㡆䕦 㩚Ⳋ㠦 Ỏ㼦 ‶㧒䞲 ㌗䌲⯒ ⽊㧊 Ⳇ, 2-HT- 61%㠦㍲☚ ゚ᾦ㩗 㟧䢎䞮┺. ⁎⩂⋮, 3- HT-70%⿖䎆 㧛ῂ䁷(TD5)ὒ 㿲ῂ䁷(TD1)Ṛ㦮 ⼖䡫 㥾 㹾㧊Ṗ 䋂Ợ ⹲㌳䞮Ⳇ Ⱎ㰖Ⱏ ┾Ἒ㧎 4-HT- 75%㠦㍲⓪ 㧛, 㿲ῂ䁷㈦ 㞚┞⧒ 䙃⹿䟻㦒⪲㦮 ⿚

Fig.10 Photograph of rolling equipment for hot rolling test(Max. rolling force=350ton)

䙂Ṩ☚ ⿞‶㧒䟊 㰖ἶ 㧞┺. ➆⧒㍲, ⽎ ㏢㨂㠦㍲

‶㧒⼖䡫㦚 㠑₆ 㥚䞲 㾲╖ ⑚㩗㞫㡆㥾㦖 㟓 60%

㧚㦚 㨂䢫㧎䞶 㑮 㧞┺.

Fig. 9⓪ ṗ Ṗ㡊䣵㑮㢖 㞫㡆㥾㠦㍲㦮 㡊Ṛ㞫㡆 䛞㦮 ⼖䡫㌗䌲⯒ ⽊㡂㭒⓪ ⁎Ⱂ㧊┺. 2-HT-61%₢

㰖⓪ 㡊㡆䛞㦮 ₎㧊, 䙃, ⚦℮⹿䟻 䡫㌗㧊 ゚ᾦ㩗

‶㧒䞲 䡫䌲⯒ ⽊㧊㰖Ⱒ, 3-HT-70%㢖 4-HT-75%㠦

㍲⓪ 㕂䞲 㭒⯚䡚㌗ὒ ⿞‶㧒 䡫㌗㧊 ⋮䌖⋮⓪◆

㧊⓪ ⽎ ㏢㨂㦮 㩗㩫 㞫㡆㥾㦖 㟓 60%Ṗ ♾㦚 Ṗ 㔲㩗㦒⪲ 㯳ⳛ䞮ἶ 㧞┺.

71# ⚞ಮ◿⚚# ⎎㚂#

714# ⎎㚂⤚ഞ#

Fig. 10㦖 㡊Ṛ㞫㡆⪺㦮 㔺䠮㧻䂮 ⹥ ῂ㫆㧊┺. 㞫 㡆⩻ 㾲╖ 35 䏺, ⪺䋂₆⓪ I320uL250(mm)㧎 2-Roll ῂ☯⹿㔳㧊┺. 㡊Ṛ㞫㡆㣿 䕦㨂䝚Ⰲ䙒 䋂₆⓪ to14.5 uwo134uuLo217(mm), 㽞₆㡾☚ 1,250^oC 㧊ἶ, ⪺㦮 㽞₆㡾☚⓪ ㌗㡾䞮㠦㍲ ⪺㦮 䘟‶㏣☚ 108.3mm/s, t_f=4mm(CRR=72%)⪲ 㧧㠛䞮㡖┺. 㞫㡆䝚⪲㎎㓺⓪ 㔲⸂⩞㧊㎮㦚 䐋䟊 㠑㠊㰚 Ὃ㩫㦚 ₆㭖䞮㡖┺. 㧧 㠛 㭧 䕦㨂 㭧㕂⿖ 䚲Ⳋ㡾☚⯒ Pyrometer(Model:

RayTemp TM38, -60 ~+1,000^oC)⪲ 䁷㩫䞮㡂 㟓 900

oC ⹎Ⱒ㧊 ♶ ἓ㤆 㨂Ṗ㡊 䞮㡖┺.

715# ⎎㚂൚ඦ# Ჹ# പ㉊#

Fig. 11 㦖 Ṗ㡊♲ 䝚Ⰲ䙒㦚 Ṗ㰖ἶ 㞫㡆⪺ 㧛ῂ 䁷㠦㍲㦮 㧎㧛ὒ 㾲㫛 㿲ῂ䁷㠦㍲㦮 㧎㿲 䤚 䕦 㨂㞫㡆 㧧㠛ὧἓ㦚 ⽊㡂㭒⓪ ㌂㰚㧊┺.

Fig. 12⓪ ⳿䚲㞫㡆㥾 60%㢖 75%₆㭖䞮㡂 䟊㍳

ὒ 㔺䠮㔺  ′⳾㦮 㔺䠮ἆὒ⯒ ゚ᾦ䞮㡖┺. 㡊Ṛ 㞫㡆 㧧㠛Ὃ㩫㦖 䟊㍳㠦㍲ ☚㿲♲ ₆⽎Ὃ㩫㠦 㭖 䟊 㔺䠮䞮㡖┺. CRR=60% 㠦㍲⓪ 䟊㍳ ⹥ 㔺䠮 ⳾

ڋ ڋډڋڐ ڋډڌ ڋډڌڐ ڋډڍ ڋډڍڐ ڋډڎ ڋډڎڐ ڋډڏ ڋډڏڐ

گڟڌ گڟڍ گڟڎ گڟڏ گڟڐ

ڧۊۉۂۄۏېڿۄڼۇٻڿۄۍۀھۏۄۊۉٻۋۊێۄۏۄۊۉ

ڠہہۀھۏۄۑۀٻێۏۍڼۄۉ

ڌڈڣگںڏڌڀٻ

ڍڈڣگںڑڌڀٻ ڎڈڣگںڒڋڀٻ

ڏڈڣگ ڒڐڀ

|sG ssG jsG

穢穢剳暒昷儆击穟箒滆V洢YW劒G 洢[笾SGYWXX噊VZWXG G

CRR% Ana lytica l product Experimenta l product

Ta rget 60%

`

Rea l va lue: 61% Rea l va lue: 60%

Ta rget 75%

Rea l va lue: 75% Rea l va lue: 73%

#

#

#

#

#

#

#

#

#

#

#

#

Fig.11 Photograph of rolling work process for hot rolling test

Fig.12 Comparison of analysis and experimental results after hot rolling

Fig.13 Results of mechanical properties & micro- structure after hot rolling test

⚦ ゚ᾦ㩗 ‶㧒⼖䡫♲ 㞫㡆䛞 ἆὒṖ 㠑㠊㪢┺.

㧊⓪ 㞴㠦㍲ 㩲㔲䞲 㾲╖Ṗ⓻ ⑚㩗㞫㡆㥾 60%㢖 㧒䂮䞾㦚 㞢 㑮 㧞┺. ⳿䚲 75%㦮 ἓ㤆 㤦䡫㩦㍶

㠦㍲ ⽊❅㧊 䟊㍳䛞㠦㍲ ㏢㨂㭒⯚ὒ ⿞‶㧒 ⼖䡫 䥾䡚㌗㧊 ⹲㌳䞮㡖㦒Ⳇ 㔺䠮ἆὒ㠦㍲☚ 㡃㔲 㥶

㌂䞲 㭒⯚ ⹥ 䥾䡚㌗㧊 ⹲㌳䞮㡂 ㌗䢎Ỗ㯳㦚 䢫 㧎 䞮㡖┺.

Fig. 13㦖 㡊Ṛ㞫㡆 㩚, 䤚㦮 ⹎㎎㫆㰗ὒ ₆Ἒ㩗

㎇㰞㠦 ╖䟊 ㌊䘊⽊㞮┺. 㞫㡆 㩚䤚 㧎㧻ṫ☚, 䟃

⽋ṫ☚䔏㎇㦖 䋆 ⼖䢪Ṗ 㠜㦒Ⳇ ἓ☚㯳Ṗ 㡃㔲

⹎⹎䞮┺. 㧛㧦䋂₆㦮 ἓ㤆☚ 㩚䡖 ⼖䢪Ṗ 㠜┺.

㧊⩂䞲 㧊㥶⓪ ⹎㎎㫆㰗 ㌂㰚㠦㍲ ⽊❅㧊 㞫㡆 㭧 㨂Ṗ㡊⪲ ⼖䡫㧊⩻㧊 ⋾㞚㧞㰖 㞠ἶ 䟊㏢♮₆

➢ⶎ㧊┺. 0^o, 90^o ⹿䟻Ṛ㦮 㫆㰗㧊 㥶㌂䞲◆ 㧊⓪ 950^oC~1,200^oC ⿖⁒㦮 㡺㓺䎢⋮㧊䔎 㫆㰗㦚 ⋮䌖

⌊ἶ 㧞┺.

71# ൚# ᤊ#

18Cr-18Mn-0.4N ἶ㰞㏢ṫ㨂㠦 ╖䟊 㡊Ṛ 䞮㠦

㍲㦮 ㏢㨂䔏㎇ 㔲䠮⿚㍳ὒ FE 㔲⸂⩞㧊㎮ ⹥ 㔺䠮 㔺′⳾㦮 㞫㡆⳾㌂㔺䠮㦚 㑮䟟䞲 ἆὒ⓪ ┺㦢ὒ ṯ┺.

(1) 㡊Ṛ㞫㡆㔲 ⿞‶㧒⼖䡫, 㑮䘟☚⿞⨟, 䕦ↂ㧚, 䥾䡚㌗ ⹲㌳⹿㰖Ṗ Ṗ⓻䞲 1 䣢╏ 㾲╖ 㞫㡆㥾㦖 15%㧊Ⳇ 㾲╖ ⑚㩗㞫㡆㥾㦖 60%㧊┺.

(2) 䙃㔶㧻㥾(WR) 5.8%, ₎㧊㔶㧻㥾(LR)㦖 176.5%

⪲㍲ ₎㧊㔶㧻㥾㧊 㟓 30.4 ⺆ 䋂Ợ ⋮䌖⋮Ⳇ 㞫㡆

㌳㌆Ὃ㩫㠦 㥶Ⰲ䞲 䣾ὒ⯒ 㩲Ὃ䞲┺.

(3) 㔺䠮㔺′⳾㦮 㞫㡆⳾㌂㧻゚⯒ ῂ㿫䞮ἶ 㡊 Ṛ 㞫㡆Ὃ㩫 㔲⸂⩞㧊㎮㠦㍲ ☚㿲䞲 Ὃ㩫㧎㧦㠦

₆㽞䞮㡂 ㎇䡫㎇ ⹥ 䡫㌗䁷Ⳋ㠦㍲ Ỗ㯳㔺䠮䞮⸖

⪲㍲ 㩲㔲䞲 㞫㡆Ὃ㩫㧎㧦㠦 ╖䞲 䌖╏㎇㦚 䢫㧎 䞮㡖┺.

(4) 㡊Ṛ㞫㡆 䤚 ⹿䟻㎇㦖 Ệ㦮 㠜㦒Ⳇ 㧎㧻ṫ

☚, ἓ☚(HB), 㧛㧦䋂₆ ❇㦖 㥶㌂䞾㦚 ⽊㡂 㡺㓺 䎢⋮㧊䔎㫆㰗㦮 䔏㎇㦚 䢫㧎䞮㡖┺.

Ⳣ ඊ ᯢ 㙶

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Z

ZWYGV穢剳暒昷儆击穟箒滆V洢YW劒G 洢[笾SGYWXX噊G Metals, pp. 92~97.

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of Japan, Vol. 48, No. 1, pp. 114~119.

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