Effect of the Reduction Amount and the Height-to-diameter Ratio on the Closure of Voids in the Hard-to-deform Zone of Upset Forging during Elongation

WANG Jie; YU Yu; JIA Lu; LI Jingdan; QI Huiping

doi:10.3969/j.issn.1674-6457.2026.06.024

PDF(2509 KB)

Journal of Netshape Forming Engineering ›› 2026, Vol. 18 ›› Issue (6) : 283-290. DOI: 10.3969/j.issn.1674-6457.2026.06.024

Effect of the Reduction Amount and the Height-to-diameter Ratio on the Closure of Voids in the Hard-to-deform Zone of Upset Forging during Elongation

WANG Jie¹, YU Yu¹, JIA Lu², LI Jingdan², QI Huiping^1,*

Author information +

History +

Abstract

To address issues such as internal voids in large steel ingots during the casting process, the work aims to take cast 25Cr2Ni4MoV steel as the research subject to conduct experiments and simulations to investigate the stress and strain distribution inside the ingot during forging, so as to determine the optimal processing parameters for void closure. Compression tests of 25Cr2Ni4MoV steel were performed with a Gleeble-3500 thermal simulation machine at temperatures ranging from 900 to 1 200 ℃ and strain rates of 0.05 to 5 s^-1. The resulting stress-strain curves were imported into Deform-3D finite element simulation software for modeling. During the upsetting process, a difficult-to-deform zone was generated at the contact area between the end face of the forging and the anvil. Pores in this zone could not be closed by upsetting alone. In the elongation stage, after the second-step press, it was observed that as the reduction ratio increased, the equivalent strain and hydrostatic stress in the difficult-to-deform region increased. Furthermore, as the height-to-diameter ratio decreased, the z-axis compressive stress and y-axis compressive stress (in the direction of the second-step press) increased. When the compression ratio was 27% and the high-to-diameter ratio was 0.6, the void could only close after the third pass. The optimal processing parameters are determined to be a reduction ratio of 27% and a height-to-diameter ratio of 0.6 after upsetting, under which voids in the difficult-to-deform region are completely closed after three elongation steps. Excessively high reduction ratios may cause insufficient forging plasticity, leading to cracks, instability during 90° rotation, bending, and enlargement of void defects.

Key words

void closure / hard-to-deform zone / numerical simulation / drawing / 25Cr2Ni4MoV steel

Cite this article

EndNote

Ris (Procite)

Bibtex

Download Citations

WANG Jie, YU Yu, JIA Lu, LI Jingdan, QI Huiping. Effect of the Reduction Amount and the Height-to-diameter Ratio on the Closure of Voids in the Hard-to-deform Zone of Upset Forging during Elongation[J]. Journal of Netshape Forming Engineering. 2026, 18(6): 283-290 https://doi.org/10.3969/j.issn.1674-6457.2026.06.024

References

[1] 谭立军, 王峻乔, 王庆群, 等. 25Cr2Ni4MoV钢大型锻件的组织与力学性能[J]. 金属热处理, 2014, 39(1): 128-131.
TAN L J, WANG J Q, WANG Q Q, et al.Microstructure and Mechanical Properties of 25Cr2Ni4MoV Steel Large Forgings[J]. Heat Treatment of Metals, 2014, 39(1): 128-131.
[2] 王秋艳, 冯庆莲, 牛玉温. 25Cr2Ni4MoV钢辊轴锻后热处理工艺研究[J]. 热处理技术与装备, 2015, 36(3): 24-27.
WANG Q Y, FENG Q L, NIU Y W.Study on Technology of Heat Treatment after Forging for Roll Shaft of 25Cr2Ni4MoV Steel[J]. Heat Treatment Technology and Equipment, 2015, 36(3): 24-27.
[3] 叶丽燕, 翟月雯, 周乐育, 等. 超大型核电转子用25Cr2Ni4MoV钢静态晶粒长大行为研究[J]. 塑性工程学报, 2021, 28(4): 146-151.
YE L Y, ZHAI Y W, ZHOU L Y, et al.Study on Static Grain Growth of 25Cr2Ni4MoV Steel for Super Large Nuclear Power Rotor[J]. Journal of Plasticity Engineering, 2021, 28(4): 146-151.
[4] YANG J R, CHEN J, LIU Y F, et al.The Effect of Laser Shock Peening on the Fatigue Performance of 25Cr2Ni4MoV Alloy[J]. Engineering Failure Analysis, 2025, 169: 109150.
[5] YE L Y, MEI B Z, YU L M.The Modeling and Simulation of Austenite Grain Growth in 25Cr2Ni4MoV Nuclear-Power Rotor Steel[J]. Metals, 2023, 13(6): 1072.
[6] LI J, XU X W, REN N, et al.A Review on Prediction of Casting Defects in Steel Ingots: From Macrosegregation to Multi-Defect Model[J]. Journal of Iron and Steel Research International, 2022, 29(12): 1901-1914.
[7] MÁDI L, MOLNÁR D. Conditions Forming to Blow-Hole Defects in Casting[J]. Materials Science Forum, 2025, 1153: 13-22.
[8] LIU X, ZHANG C J, HU S W, et al.Research Progress and Prospects on the Formation Mechanism of Macrosegregation and Shrinkage Porosity in Large Steel Ingots[J]. Progress in Natural Science: Materials International, 2024, 34(3): 470-481.
[9] 李胤宪, 胡杰, 蒋燕超, 等. 508-Ⅲ坯料锻造过程孔洞变化规律的数值模拟[J]. 金属加工(热加工), 2023(11): 120-125.
LI Y X, HU J, JIANG Y C, et al.Numerical Simulation of the Variation Law of Voids during the Forging Process of 508-Ⅲ Billet[J]. MW Metal Forming, 2023(11): 120-125.
[10] KITAYAMA S.Technical Review on Design Optimization in Forging[J]. The International Journal of Advanced Manufacturing Technology, 2024, 132(9): 4161-4189.
[11] 施文鹏, 黎恒逸, 张元东, 等. 基于DEFORM数值模拟的15Cr14Co12Mo5Ni钢齿轮锻造方案优化[J]. 精密成形工程, 2025, 17(4): 78-86.
SHI W P, LI H Y, ZHANG Y D, et al.Optimization of 15Cr14Co12Mo5Ni Steel Gear Forging Scheme Based on DEFORM Numerical Simulation[J]. Journal of Netshape Forming Engineering, 2025, 17(4): 78-86.
[12] DUDRA S P, IM Y T.Analysis of Void Closure in Open-Die Forging[J]. International Journal of Machine Tools and Manufacture, 1990, 30(1): 65-75.
[13] 冯超. 大型钢锭锻造开坯过程中内部空洞型缺陷的演化规律与消除方法[D]. 上海: 上海交通大学, 2017.
FENG C.Research on the Evolution and Elimination of Void Defects in Large Ingots during Hot Forging[D]. Shanghai: Shanghai Jiao Tong University, 2017.
[14] KIM I, PARK J, KIM J, et al.A Generalized Void Closure Model in Hot Forging Process of Superalloys[J]. Journal of Materials Research and Technology, 2025, 36: 6802-6820.
[15] 李殿中, 马璇, 徐斌, 等. 高效愈合钢锭内部缺陷的锻造工艺设计[J]. 金属学报, 2016, 52(10): 1199-1206.
LI D Z, MA X, XU B, et al.Design of Forging Methods of Healing Defects in Ingots Effectively[J]. Acta Metallurgica Sinica, 2016, 52(10): 1199-1206.
[16] 张效迅. 大锻件锻造成形过程中内部空洞型缺陷演化规律的研究[D]. 上海: 上海交通大学, 2009.
ZHANG X X.Research on Void Evolution in Large Ingot during Hot Forging[D]. Shanghai: Shanghai Jiao Tong University, 2009.
[17] 宋克亮, 高彩茹, 邱春林, 等. H13钢锻造过程中空洞缺陷的演变规律[J]. 机械工程材料, 2020, 44(S2): 1-6.
SONG K L, GAO C R, QIU C L, et al.Evolution of Cavity Defects in H13 Steel during Forging[J]. Materials for Mechanical Engineering, 2020, 44(S2): 1-6.
[18] TANAKA M, ONO S, TSUNENO M.Factors Contributing to Crushing of Voids during Forging[J]. Journal of the Japan Society for Technology of Plasticity, 1986, 27(306): 852-859.
[19] TANAKA M, ONO S, TSUNENO M.A Numerical Analysis on Void Crushing during Side Compression of Round Bar by Flat Dies[J]. Journal of the Japan Society for Technology of Plasticity, 1987, 28(314): 238-244.
[20] 方旭升, 汪盼盼, 奚涛涛, 等. 大锻件用25Cr2Ni4MoV钢镦粗与拔长工艺分析[J]. 塑性工程学报, 2022, 29(8): 47-55.
FANG X S, WANG P P, XI T T, et al.Analysis on Upsetting and Stretching Process of 25Cr2Ni4MoV Steel for Heavy Forgings[J]. Journal of Plasticity Engineering, 2022, 29(8): 47-55.
[21] 徐斌, 孙明月, 李殿中. 锻造过程中钢锭内部孔洞型缺陷闭合规律研究[J]. 金属学报, 2012, 48(10): 1194-1200.
XU B, SUN M Y, LI D Z.The Void Close Behavior of Large Ingots during Hot Forging[J]. Acta Metallurgica Sinica, 2012, 48(10): 1194-1200.
[22] AHMADI H, DEHGHAN S, RANJBAR H.Enhancement of Upsetting Technology for Minimizing Internal Defects in Heavy Ingot Casting: Simulation, Optimization, and Experimental Validation[J]. International Journal of Material Forming, 2025, 18(1): 21.
[23] 刘前军, 邱垚, 信瑞山, 等. 大型锻件内部孔隙性缺陷修复效果对疲劳性能的影响[J]. 锻压技术, 2022, 47(11): 16-21.
LIU Q J, QIU Y, XIN R S, et al.Influence of Repair Effect for Internal Porosity Defects on Fatigue Performance of Heavy Forgings[J]. Forging & Stamping Technology, 2022, 47(11): 16-21.
[24] 陈飞, 焦永星, 李飞, 等. 不同镦粗工艺对钢锭内部孔洞缺陷闭合行为的影响[J]. 热加工工艺, 2025, 54(3): 114-119.
CHEN F, JIAO Y X, LI F, et al.Influence of Different Upsetting Process on Closing Behavior of Void Defects in Ingot[J]. Hot Working Technology, 2025, 54(3): 114-119.
[25] 李辉. 主轴锻件25Cr2Ni4MoV钢断裂准则及锻造工艺数值模拟研究[D]. 太原: 太原科技大学, 2025: 11-19.
LI H.Fracture Criterion and Numerical Simulation of Forging Process of 25Cr2Ni4MoV Steel for Spindle Forgins[D]. Taiyuan: Taiyuan University of Science and Technology, 2025: 11-19 .
[26] 李世键, 孙明月, 刘宏伟, 等. 25Cr2Ni4MoV钢锻造过程孔洞缺陷愈合规律研究[J]. 金属学报, 2011, 47(7): 946-953.
LI S J, SUN M Y, LIU H W, et al.Study on Void Healing Behavior during Forging Process for 25Cr2Ni4MoV Steel[J]. Acta Metallurgica Sinica, 2011, 47(7): 946-953.
[27] LEE Y S, LEE S U, VAN TYNE C J, et al. Internal Void Closure during the Forging of Large Cast Ingots Using a Simulation Approach[J]. Journal of Materials Processing Technology, 2011, 211(6): 1136-1145.