Toyo Seiko Web Site






Characteristics of Toyo Seiko | Toyo Seiko Proceedings Library

TOYO SEIKO CO.,LTD. Company Outline

Head Office & Plant
  • 3-195-1 Umaganji, Yatomi-city , Aichi
    490-1412 , Japan
  • TEL:+81-567-52-3451
  • FAX:+81-567-52-3457
  • February 15,1975
  • 25 million yen
  • 62 (March 2017 including part time)
Yearly turnover
  • 3,630 million yen (March 2017)
  • Yoshihiro Watanabe
Office and Plant area
  • 6,020sq.m
Toyo Seiko

TOYO SEIKO CO.,LTD in a larger map


Office & Plant
  • 22 Koyo-cho, Matsusaka city, Mie prefecture
    515-0053 , Japan
    inside of Aircraft Parts Manufacturing Cooperative (APMC)
  • TEL:+81-598-30-6281
  • FAX:+81-598-30-6286
Toyo Seiko


Thailand Plant
  • 802 Moo4, Bangpoo Industrial Estate, Soi 14,
    Sukhumvit Road, Praeksa,
    Muang, Samutprakarn 10280
  • February 2011
  • 112 million THB
  • 23 (Dec 2016)
Yearly turnover
  • 260million THB (Dec 2016)
  • TOYO SEIKO CO.,LTD.(61.25%),
  • Others(38.75%)
Managing Director
  • Hiroyuki Watanabe
Office and Plant area
  • 4,676sq.m (2.92Rai)
Toyo Seiko Thailand

TOYO SEIKO (THAILAND) CO.,LTD. in a larger map

37km far from the center of Bangkok.

20km far from Suvarnabhumi International Airport.


USA Office
  • April 2014
  • 750,000 USD
  • 5 (April 2017)
  • Yoshihiro Watanabe
Toyo Seiko North Amrica

TOYO SEIKO NORTH AMERICA Inc. in a larger map

Characteristics of Toyo Seiko

Consistent Production from Material to Product
We can always correspond to customer's requirement such as hardness and sizes.
Realization of manufacturing super hard shot (HV800 or above)
High hardness RCW is most suitable for hard shot peening to obtain high compressive residual stress. Toyo Seiko is the only company in the world to manufacture such hard shot media as hard as HV850.
Long years of shot peening reserch collaborated wiht an university.
We have an ability to select the most suitable peening condition for customers utilizing PSPC X-ray stress analyzer.

Toyo Seiko Proceedings Library

  • Title: Sealed Na Source for Positron Annihilation Lifetime Spectroscopy
  • Author: Masato Yamawaki, Yoshinori Kobayashi, Kenji Ito, Mikio Matsumoto, Kidetake Ishizu, Akiyo Umino, Kanehisa Hattori, Yoshihiro Watanabe
  • Source: National Institute of Advanced Industrial Science and Technology
  • Publication year 2012
  • Abstract:
    Sealed radioactive sources of 22Na for positron annihilation lifetime spectroscopy (PALS), free from the legal regulations, are commercially available from an American company. However, thick foils are used to seal 22Na in these sources and large fractions of the positrons annihilate in the sealing materials. Further, it is pointed out that a long lifetime component over 1 ns appears in the positron lifetime spectrum acquired with the Kapton sealed source (POSK-22, IPL Inc.). In this research, attempts were made to develop high quality sealed positron sources, potentially free from regulations, for ubiquitous application of PALS. The sources prepared in the present work are of high quality and applicable to our new PALS, which does not requite sample utting and is potentially applicable to truly nondestructive, onsite inspection of various materials.
  • Title: The Effect of Frozen Ultrasonic Shot Peening Treatment on Two Way Characteristic at Shape Memory Alloy
  • Author: Watanabe, Hattori, Handa, Yoshimi, Ikeda, Fujii
  • Source: Conf Proc 2011: ICSP-11 South Bend, IN USA (pgs. 365-370)
  • Publication year 2011
  • Abstract:
    This paper shows the possibility whether shot peening treatment would be alternative method to bias spring. We conducted Ultrasonic Shot Peening (USP) at low temperature to induce compressive residual stress, which react as an outer force. Further to obtain the useful residual stress on SMA behavior, we developed the Frozen Ultrasonic Shot Peening (FUSP) treatment to meet the SMA function. As a result, the effective two way characteristic of SMA by frozen shot peening treatment was confirmed. And in order to confirm the durability of SMA, we conducted the fatigue test.
  • Source link: not available
  • Title: Effect Of Ultrasonic Shot Peening On The Fatigue Characteristics Of Welded Sts304 For Rolling Stock
  • Author: Cheong, DS Lee, JH Lee, Handa, Watanabe
  • Source: Conf Proc: ICSP-10 Tokyo, Japan 2008
  • Publication year 2008
  • Abstract:
    Fatigue fracture of structures can be easily expected if the structures have heat affected zone, i.e. welded part. However, the fatigue characteristic and durability can be improved by applying shot peening process because it induces the compressive residual stress on the surface of structures. In this paper work, the effects of ultrasonic peening on the fatigue life of the step in rolling stock are investigated. STS304 welded specimens are used for this study. Conventional shot peening process is also accomplished to compare with ultrasonic peening(CSP). To obtain S-N data, the bending fatigue test was done for conventional shot peened and ultrasonic peened specimens with the same Almen intensity. Compressive residual stress is also measured to find the factors improving the fatigue life. The results show that the fatigue life for ultrasonic shot peened specimens increases tremendously by comparing with the fatigue life of unpeened specimen.
  • Title: Effect Of Ultra Shot Peening On Casting Shape Memory Alloy
  • Author: Y Watanabe, K Hattori, M Handa, Y Yoshimi, T Inaba
  • Source: Conf Proc: ICSP-10 Tokyo, Japan 2008
  • Publication year 2008
  • Abstract:
    In order to overcome difficulties that have hindered precision casting of shape memory alloys, we made a ingots created with Self Propagating High Temperature Synthetic Method (SHS) which eventually led us to the success of precision casting utilizing lost wax process. Also we have succeeded in creating functional products that are treated with the ultrasonic shot peening process, improving the resiliency against deformation and fatigue strength. Although the common casting products are created using many different kinds of metals and alloys, casting products utilizing shape memory alloys have not been widely adopted due to a lack of successfully produced products. The reasons for this are that there was much difficulty in developing equal property structures that does not allow gravity segregation of Ni-Ti. Also its essential characteristics (being the shape memory and super elasticity), the makeup of component had to overcome the structural weaknesses in order to withstand from possible deformation.
  • Title: Effect of Ultra Shot Peening on Contact Surface Strength
  • Author: Watanabe, Hattori, Handa, Yoshida, Taki, Duchazeau
  • Source: Conf Proc: ICSP-9 (pg 179-184)
  • Publication year 2005
  • Abstract:
    For carburized gear, shot peening treatment is widely recognized for improvement of bending fatigue strength. However the effect of shot peening on tooth surface strength gears have not been clarified due to complicated mechanism. On the other hand, recently, Ultrasonic Shot Peening (USP) technology was developed by SONATS, France. The main characteristics of USP could be the smooth surface after operating compared to the conventional shot peening (CSP). In this study, roller fatigue test using a disk machine with rolling and sliding was carried out. As a result, surface strength of roller is deteriorated by shot peening treatment. But at the comparison between CSP and USP, the strength of USP would be remarkably higher than CSP.
  • Title: Suggestion of Image Processing System for Measurement of Coverage
  • Author: Handa, Watanabe, Hattori, Toyo Seiko Co., Ltd.
  • Source: The Shot Peener magazine, Vol 19 / Issue 3, Summer 2005
  • Publication year 2005
  • Abstract:
    Generally speaking, the management of shot peening would be conducted by arc height intensity, coverage and deformation of part. As standard method of measurement of coverage, it should be required to use the strip that has the same hardness and material of the target. However, usually normal almen strip is used in place of correct specimen for coverage measurement. As standard method of coverage measurement, it is required to calculate by checking the weight rate of piece that was cut from an enlarged photo. Further at simplified method it is requested to decide the coverage by comparing with the standard photo. The former method takes a longer measurement time and the latter is basically depend on the skill. So, in this paper we would suggest new measurement method to avoid above two problem by using mirror polished almen strip and image processing.
  • Title: Cut-Wire Type Ferrous Shot for Blasting and a Process of Using a Cut-Wire Type Ferrous Shot for Blasting
  • Author: T Watanabe; S Murai; N Murai; Y Watanabe; Hattori
  • Source: US Patent 6,394,881 B1
  • Publication year 2002
  • Abstract:
    The present invention discloses a cut wire method of producing a ferrous shot and a cut-wire type ferrous shot for shot-blasting having a hardness of Hv 200 to 300 and a low work hardening ability. Further, the present invention describes a process of using a cut-wire type ferrous shots, comprising preparing the cut-wire type ferrous shots and a ferrous object and projecting the shots to the ferrous object to remove foreign material from the ferrous object.
  • Title: Effect of Ultrasonic Shot Peening on Fatigue Strength of High Strength Steel
  • Author: Watanabe Hattori Handa Hasegawa Takaji Ikeda Ducha
  • Source: Conf Proc: ICSP-8 Sept. 16-20, 2002 Garmisch-Partenkirchen, Germany
  • Publication year 2002
  • Abstract:
    A study had been made to evaluate the effect of the Ultrasonic shot peening treatment, developed by SONATS, on fatigue strength. This new shot treatment could give the smooth surface after shot peening because of using the polished ball bearings. To investigate the effect and the merit of new treatment, fatigue test were conducted on cantilever type rotating bending fatigue testing machine. It was confirmed that fatigue strength peened by ultrasonic shot treatment is almost the same as that peened by conventional air peening device. Further, mechanism of the fracture was confirmed between roughed specimens by conventional peening and the smooth one by ultrasonic peening.
  • Title: Searching for the Most Suitable Condition and the Suggestion of Each Application in Ultrasonic Shot Peening
  • Author: Hattori, Watanabe, Handa, Duchazeaubeneix
  • Source: Conf Proc: ICSP-8 Sept. 16-20, 2002 Garmisch-Partenkirchen, Germany
  • Publication year 2002
  • Abstract:
    Ultrasonic shot peening, named Stressonic, developed by SONATS, is being popularized among aeronautic industries for production parts and maintenance application because of its compact equipment that allows treatment partially and it can be integrated into production line. However, Stressonic has a big difference in processing method compared to that of classical shot peening. Therefore, the peening management, which influences the peening effect, needs to be renewed. In this report, treatment conditions as amplitude, shot media (material, diameter), injecting distance, are set as Stressonic management items. Then the most suitable Stressonic condition is experimented by intensity and residual stress distribution obtained from the management above. Stressonic application is also studied using parts, such as gears and springs, and confirmed its quality after Stressonic process. As a result of study and experiment, Stressonic application has an outstanding peening effect.
  • Title: An Effect of Peening on Fretting Fatigue
  • Author: Y Watanabe, N Hasegawa, H Endo, E Marui, Y Aoki
  • Source: Conf Proc: ICSP-7 (pg 127-134)
  • Publication year 1999
  • Abstract:
    A study has been made on the effect of shot peening on fretting fatigue, a complex deterioration phenomenon caused by the small amplitude relative motion of two metallic surfaces. To investigate this effect, two types peened specimens, having different surface roughness, and peened - annealed specimens were prepared. It was confirmed that shot peening improved fretting fatigue, and fretting fatigue strength increases with increasing roughness.
  • Title: The Temperature Change on Surface of Workpiece During Peening
  • Author: N. Hasegawa, K. Hattori, Y. Watanabe, K. Fukuyama
  • Source: Conf Proc: ICSP-7 (pg 54-59)
  • Publication year 1999
  • Abstract:
    A study has been made to investigate the temperature change on surface of specimen using a thermograph during shot peening. It was confirmed that the temperature change of annealed specimens is greater than that of carburized specimens, as well as an occurence of temperature ascent when peening with smaller shot. However, the softened smallest shot experienced only slight temperature changes. This change was caused mainly by abrasion.
  • Title: Simulation of Residual Stress Distribution on Shot Peening
  • Author: Y. Watanabe, N. Hasegawa
  • Source: Conf Proc: ICSP-6, (p.530-535)
  • Publication year 1996
  • Abstract:
    The present research aims at obtaining a theoretical solution on basis of actural measurements of residual stress by shot peening. Firstly, it was conducted that residual stress on two different strength of plate specimens have been shot peened are measured by X-ray difractometer and the effect of a few type of shot peening conditions on profiles are confirmed. The equation to simulate profiles was obtained by the superpostition method of simple three stress, based on the equation that Y.F.Al-Obaid suggested. It was confirmed that the predicted stress profile shows good correspondence with experimental value in case of every shot peening conditions in this study.
  • Title: Effect of Shot Peening on Delayed Fracture of High Strength Steel
  • Author: Y. Watanabe and N. Hasegawa
  • Source: Conf Proc: ICSP-5, (p.219-225)
  • Publication year 1993
  • Abstract:
    A study has been made on the effect of shot peening on delayed fracture susceptibility of high strength steel at a level of 1300MPa. By means of bending type testing, it was confirmed that the delayed fracture resistance improves due to an increase in compressive residual stress by shot peening. Further study indicates that the increased resistance to delayed fracture of shot peened specimens is caused mainly by the prologed incubation period to crack initiation
  • Title: Effect of Shot Peening on Fatigue Strength of Carbon Steel at Elevated Temperature
  • Author: N. Hasegawa, Y. Watanabe, Y. Kato
  • Source: Conf Proc: ICSP-5, (p.134-139)
  • Publication year 1993
  • Abstract:
    A study has been made on the effect of shot peening on fatigue strength at elevated temperature on 0.50% carbon steel. By means of bending rotating testing over the temperature range from 20 deg.C to 450 deg.C, it was confirmed that shot peening increase the fatigue strength of specimens at room temperature due to work hardening and compressive residual stress at surface layer. And fatigue strength of shot peened specimens decrease with increasing testing temperature due to the reduction of the magnitude of residual stress. In comparison to annealed specimens, however, it was observed that the bendfit of shot peening is appeared up to 400 deg.C by work hardening.
  • Title: The Development of New Type Almen Strip for Measurement of Peening Intensity on Hard Shot Peening
  • Author: Watanabe, Hasegawa, Namiki, Hatano
  • Source: The Shot Peener magazine, Vol 06/Issue 4, Winter 1992/93
  • Publication year 1992
  • Abstract:
    In the hard shot peening, it has been pointed out that Almen A type strip is not proper as an index of peening effect, because the arc height measured by Almen A strip is not in good correspondence to surface residual stress. Based on this background, the relation between residual stress and the arc height measured by conventional C strip and the high hard trial strip with hardness of HRC 60 was investigated. It was concluded that the arc height measured by high hard trail strip was in good agreement with the maximum compressive stress and the magnitude of stressed layer.
  • Title: The Influence Of Broken Shots On Peening Effect Of Hard Shot Peening
  • Author: Watanabe, Hasegawa, Namiki, Natano
  • Source: Conf Proc: ICSP-4, (p. 63-72)
  • Publication year 1990
  • Abstract:
    Hard shot peening characterized by its larger shot injecting energy with arc height higher than 0.7 mmA is becoming popular as one of the methods to enhance the fatigue durability especially for case hardened components. During this process many shots are broken compared to conventional peening process. In this study, to clarify the influence of broken shots on fatigue properties, two types shots having two different hardness respectively are prepared. Ervine tests reveals that one of them has many broken particles and another has a little. Using these two types shots specimens were hardly peened and fatigue tests are carried out to obtain S-N curve and Weibull charts. The specimens peened with shots containing many broken shots show wider distribution of fatigue life than the ones peened with shots containing of a little. It is concluded that broken shots degrade the stability of peening effect in hard shot peening. Descriptors: Hard shot peening; Carburized steel; Residual stress; Retained austenite; Fatigue test; S-N curve; Weibull chart