CN-121992292-A - Hard rock TBM hob ring and preparation method thereof

CN121992292ACN 121992292 ACN121992292 ACN 121992292ACN-121992292-A

Abstract

The invention discloses a TBM hob ring for hard rock and a preparation method thereof, and belongs to the technical field of tunneling equipment key part materials. The alloy steel comprises the following chemical components in percentage by weight ：C 0.50%~0.65%,Si 0.80%~1.20%,Mn 0.50%~0.80%,Cr 4.50%~5.50%,Mo 1.20%~1.80%,V 0.80%~1.50%,W 0.50%~1.20%,Nb 0.05%~0.15%,La 0.02%~0.10%,Y 0.03%~0.08%,Ni ≤0.50%,P ≤0.020%,S ≤0.010%, and the balance of Fe and unavoidable impurities. The preparation method comprises the steps of adding lanthanum-iron alloy and yttrium-iron alloy during arc furnace smelting, electroslag remelting, multidirectional forging (the forging ratio is more than or equal to 5), annealing treatment and final heat treatment (quenching + (-80 to-196 ℃) deep cooling treatment, rare earth stabilization treatment and three tempering). According to the invention, nano-scale carbide is precipitated through the cooperation of W and Nb, la and Y are compounded to realize purification, deterioration, pinning and stabilization, grains and carbide are refined, so that the hardness of the cutter ring is 60-65HRC, the impact toughness is more than or equal to 25J, the wear resistance and the service life of the cutter ring are obviously improved compared with those of a common H13 steel cutter ring, and the service life and the rock breaking efficiency under hard rock geology are obviously improved.

Inventors

JIANG TAO
ZHANG RUI
LU GAOMING
LIU CHAOYIN
FENG HAIQING
WEI SHIZHONG
LIU MU
YU HUA
MA MENGMENG
XU LIUJIE
JIN JUNJIE
LI SHIWEI

Assignees

河南科技大学
中国水利水电第十一工程局有限公司

Dates

Publication Date: 20260508
Application Date: 20251222

Claims (9)

1. A hard rock TBM hob ring is characterized in that the chemical components of the hob ring are ：C 0.50%～0.65%,Si 0.80%～1.20%,Mn 0.50%～0.80%,Cr 4.50%～5.50%,Mo 1.20%～1.80%,V 0.80%～1.50%,W 0.50%～1.20%,Nb 0.05%～0.15%,La 0.02%～0.10%,Y 0.03%～0.08%,Ni ≤0.50%,P ≤0.020%,S ≤0.010%, and the balance of Fe and unavoidable impurities in percentage by weight.
2. The hard rock TBM hob ring of claim 1 wherein La and Y are present in a weight percentage of 0.5≤Y/La≤2.0.
3. The hard rock TBM hob ring according to claim 1, characterized in that the hardness is 60-65 HRC, and the impact toughness AKU is not less than 25J.
4. A method of making a hard rock TBM hob ring according to claim 1 or 2, characterized in that it comprises the steps of: S1, smelting and refining, namely smelting by adopting an arc furnace or an intermediate frequency induction furnace, and then remelting and refining electroslag to obtain a steel ingot; S2, forging, namely heating the steel ingot to 1150-1200 ℃ and performing multidirectional upsetting and drawing forging, wherein the forging ratio is more than or equal to 5, and forming a blank; S3, annealing treatment, namely heating the blank to 860-890 ℃ and preserving heat, and then discharging and air cooling the blank to below 500 ℃ in a furnace to soften tissues for convenient machining; s4, machining, namely rough machining is carried out on the annealed blank body to form a cutter ring blank; s5, final heat treatment, namely sequentially performing the following steps: s51, quenching, namely austenitizing in a vacuum furnace at 1020-1080 ℃ and preserving heat for 2-4 hours, and then quenching to obtain a high-hardness martensitic matrix; S52, performing cryogenic treatment, namely placing the quenched workpiece at-80 ℃ to-196 ℃ for 1-4 hours to promote transformation from retained austenite to martensite, and improving hardness and dimensional stability; S53, rare earth stabilization treatment, namely preserving heat for 1-2 hours in a vacuum environment or in a protective atmosphere with oxygen partial pressure less than or equal to 10Pa at 300-400 ℃, and then cooling to 250 ℃ in an air way, so that La and Y elements are fully biased at a grain boundary and a phase interface, and tissue stabilization is realized; s54, tempering for three times, namely tempering for three times at 520-580 ℃ and keeping the temperature for at least 2 hours in each tempering so as to promote carbide to disperse and separate out, realize secondary hardening and eliminate internal stress; And S6, finish machining, namely, finely grinding the cutter ring blank subjected to heat treatment to the final size to obtain the final hard rock TBM hob ring.
5. The method according to claim 4, wherein in step S1, la and Y are added in the form of lanthanum-iron alloy and yttrium-iron alloy, respectively.
6. The method according to claim 4, wherein the incubation time in step S3 is 2 to 5 hours.
7. The method according to claim 4, wherein the quenching in step S51 is high-pressure gas quenching or fractional oil quenching.
8. The method according to claim 4, wherein the protective atmosphere in the step S53 is an inert gas atmosphere or a nitrogen-hydrogen mixed atmosphere.
9. The method according to claim 4, wherein the three tempering in step S54 is continuously performed.

Description

Hard rock TBM hob ring and preparation method thereof Technical Field The invention belongs to the technical field of key component materials of tunneling equipment, and particularly relates to a hob ring of a hard rock full-face Tunnel Boring Machine (TBM) and a preparation method thereof. Background Full face Tunnel Boring Machines (TBMs) are the core equipment of modern tunnel engineering, with their hob rings being the key wearing parts that directly contact and break the rock. Under hard rock geological conditions, the cutter ring needs to bear extremely high impact loads, huge compressive stresses and severe abrasive wear. Premature failure of the cutter ring, such as excessive wear, tipping or breakage, can lead to frequent shutdown and cutter changing, not only greatly increasing construction cost, but also seriously compromising engineering progress. Currently, the mainstream cutter ring material system is mostly based on hot work die steel, such as H13 steel which is widely used. The typical chemical composition is C0.38% -0.42%, cr 4.80% -5.50%, mo 1.20% -1.60% and V0.85% -1.15%. The material has the obvious defects of firstly, the hardness is usually only 52-55HRC, the wear resistance is insufficient, the wear rate is as high as 0.8-1.2mm/km in actual hard rock tunneling, secondly, the impact toughness is lower, the typical value is 15-18J, the cutter ring is easy to break or fracture when bearing high impact load, the average service life of the H13 steel cutter ring is shorter due to the deficiency of the comprehensive performance, the replacement cost can be more than 30% of the total cost of tunnel construction. The prior art has explored some to improve knife ring performance. For example, the invention of publication No. CN1330787C focuses on Cr-Mo-V system, but no W, nb or rare earth element is added, the composition is relatively simple, and the improvement of wear resistance and toughness is limited. For another example, the invention patent publication CN120290981a emphasizes the micro-alloying of vanadium and niobium to refine the grains, but the Nb content is higher (v+nb reaches 1.70%), and the W element is absent, and the rare earth element is not added, and the narrower carbon content range limits the further increase of hardness to some extent. For another example, the invention patent with publication number CN117721390a optimizes toughness by adding Ce and Ti, but the alloy element types are less, and the heat treatment process is more conventional, and the overall improvement effect on performance is limited. In summary, the prior knife ring material has the core contradiction that the hardness and the toughness are difficult to be compatible, namely, the toughness is often sacrificed when the hardness is improved, the brittleness is increased, and the toughness is ensured, and the extremely high wear resistance is difficult to obtain. Therefore, development of a novel cutter ring material with ultra-high hardness, excellent toughness and high fatigue resistance and a matched preparation process thereof so as to meet the requirements of extremely hard rock and high-strength tunneling has become a key technical problem to be overcome in the field. Disclosure of Invention The invention aims to overcome the defects that the hardness and toughness of the existing cutter ring material are difficult to be compatible, the wear resistance is poor and the service life is short, and provides a TBM hob cutter ring for hard rock and a preparation method thereof. Through the synergistic ratio of specific components and the optimized preparation process, the excellent performances of cutter ring hardness of 60-65HRC and impact toughness of more than or equal to 25J are realized, the wear resistance is improved by more than 30 percent compared with H13 steel, the service life of the cutter ring is obviously prolonged under the geological condition of hard rock, and the rock breaking efficiency is improved. In order to achieve the above purpose, the invention adopts the following specific scheme: On the one hand, the invention provides a hard rock TBM hob ring, which comprises the chemical components of ：C 0.50%～0.65%,Si 0.80%～1.20%,Mn 0.50%～0.80%,Cr 4.50%～5.50%,Mo 1.20%～1.80%,V 0.80%～1.50%,W 0.50%～1.20%,Nb 0.05%～0.15%,La 0.02%～0.10%,Y 0.03%～0.08%,Ni ≤0.50%,P ≤0.020%,S ≤0.010%, weight percent of Fe and unavoidable impurities. Further, the weight percentage of La and Y is more than or equal to 0.5 and less than or equal to 2.0. Further, the hardness is 60-65 HRC, and the impact toughness AKU is more than or equal to 25J. In another aspect, the invention provides a method for preparing the hard rock TBM hob ring, comprising the following steps: S1, smelting and refining, namely smelting by adopting an arc furnace or an intermediate frequency induction furnace, and then remelting and refining electroslag to obtain a steel ingot; S2, forging, namely heating the steel ingot to 1150-1200 ℃ and perf