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The effectivity of used-oil as quenching medium of 42-CrMo4 steel for automotive materials Hariningsih, Hariningsih; Sumpena, Sumpena; Sukarjo, Heribertus
Applied Research and Smart Technology (ARSTech) Vol. 1 No. 1 (2020): Applied Research and Smart Technology (ARSTech)
Publisher : Department of Mechanical Engineering Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/arstech.v1i1.11

The research aims to investigate the effect of the cooling medium on the hardness characteristic and microstructure of the 42CrMo4 steel due to hardening treatment at a temperature of 830Â°C and holding time of 30 minutes. Various oil such as SAE-10W40, SAE-20W50, SAE-40, and used oil was used in the cooling medium. The changes in product size, hardness, and microstructure have been carefully assessed. The results indicated that the viscosity of the coolant medium strongly influenced the cooling rate of the cooling medium, hardness, and microstructure. SAE-10W40 oil and SAE-20W50 oil only needed 2 hours to return within room temperatures before quenching, whereas SAE-40 oil and used oil took 3 hours. The sample size did not change after hardening-quenching. However, there was a residual carbon layer on the sample surfaces. Quenching caused the changes of microstructure from pearlite and ferrite to ultrafine double phase, consisting of martensite and austenite, which were unable to transform during rapid cooling. The highest hardness value was achieved by the treated product, which was quenched in SAE-10W40, which had 54.59 HRC. The high hardness was attributed to the content of 95% martensite. However, used-oil caused in similar hardness as SAE-20W50.

KARAKTERISASI LIMBAH DEBU DARI DUST COLLECTOR INDUSTRI PENGECORAN LOGAM Rizka, Tasha; Awaludin, Muhammad; Hariningsih, Hariningsih
JURNAL FOUNDRY Vol. 7 No. 2 (2024): JURNAL FOUNDRY
Publisher : LPPM Politeknik Manufaktur Ceper

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.62944/jf.v7i2.108

Debu merupakan limbah hasil industri yang memiliki kandungan silika yang tinggi. Debu dari dust collector di area cetakan greensand di industri pengecoran logam memiliki kandungan silika dan kadar lempung. Kandungan tersebut berasal dari komposisi penyusun pasir cetak greensand, yaitu dari pasir silika dan bentonit. Oleh karena itu penelitian ini bertujuan untuk mengetahui karakter debu dari dust collector area cetakan greensand pada indutri pengecoran logam. Pengujian yang dilakukan meliputi grain fineness number (GFN), clay content, MB active clay, volitile combustible material (VCM), dan loss on ignation (LOI). Hasil pengujian clay content dan MB active clay menunjukan bahwa debu dust collector memiliki kandungan lempung sebesar 76,54%, 41% dari kandungan lempung tersebut masih aktif sebagai perekat (active clay). Karena kandungan active clay-nya yang cukup tinggi, maka debu dust collector dapat dimanfaatkan sebagai bahan pengikat pada pasir cetak greensand. Namun, debu tidak dapat digunakan sebagai bahan pengikat utama pada pasir cetak greensand. Dimana hasil uji VCM menunjukkan bahwa debu menghasilkan 28,48% gas ketika dipanaskan pada suhu 649 °C. Sedangkan pada pengujian LOI, debu terbakar 57,00% saat dipanaskan pada suhu 1010°C. Banyaknya debu yang terbakar dan gas yang muncul dapat menyebabkan cacat cor gas hole pada benda cor.

The effectivity of used-oil as quenching medium of 42-CrMo4 steel for automotive materials Hariningsih, Hariningsih; Sumpena, Sumpena; Sukarjo, Heribertus
Applied Research and Smart Technology (ARSTech) Vol. 1 No. 1 (2020): Applied Research and Smart Technology
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/arstech.v1i1.11

The research aims to investigate the effect of the cooling medium on the hardness characteristic and microstructure of the 42CrMo4 steel due to hardening treatment at a temperature of 830°C and holding time of 30 minutes. Various oil such as SAE-10W40, SAE-20W50, SAE-40, and used oil was used in the cooling medium. The changes in product size, hardness, and microstructure have been carefully assessed. The results indicated that the viscosity of the coolant medium strongly influenced the cooling rate of the cooling medium, hardness, and microstructure. SAE-10W40 oil and SAE-20W50 oil only needed 2 hours to return within room temperatures before quenching, whereas SAE-40 oil and used oil took 3 hours. The sample size did not change after hardening-quenching. However, there was a residual carbon layer on the sample surfaces. Quenching caused the changes of microstructure from pearlite and ferrite to ultrafine double phase, consisting of martensite and austenite, which were unable to transform during rapid cooling. The highest hardness value was achieved by the treated product, which was quenched in SAE-10W40, which had 54.59 HRC. The high hardness was attributed to the content of 95% martensite. However, used-oil caused in similar hardness as SAE-20W50.

Effects of heat treatment on microstructure and hardness of D2 tools Hariningsih, Hariningsih; Lutiyatmi, Lutiyatmi; Daryanto, Tri
Applied Research and Smart Technology (ARSTech) Vol. 3 No. 1 (2022): Applied Research and Smart Technology
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/arstech.v3i1.761

D2 high chromium tool steel is widely used to produce tools and components that work at significant dynamic loads, such as dies, punches and rollers. The steel must have a good combination of strength and toughness, which heat treatment can obtain. Therefore, this study discusses the effect of normalising, hardening, and tempering on the microstructure and hardness of D2 tools. Normalising and hardening were carried out respectively at 1020°C for 30 minutes, followed by rapid cooling using oil. Tempering was realised by reheating the quenched sample at 250°C and 400°C with variations in holding time of 15 minutes, 30 minutes, and 45 minutes. The hardness of the specimens was measured using a Rockwell hardness tester, whereas the microstructure was observed with an optical microscope. The results indicated that the microstructure changes to martensite and carbide after quenching, while the microstructure becomes tempered martensite and carbide after tempering. Normalising and hardening have almost no impact on hardness, and the increase in temperature and holding time causes a decrease in hardness. The reduction in hardness is noticeable for steels tempered to 400 °C and held for 45 minutes.

PENDAMPINGAN PEMANFAATAN TERAK ATAU LIMBAH PENGECORAN TANUR KUPOLA DI KECAMATAN CEPER KLATEN JAWA TENGAH SEBAGAI AGREGAT KASAR PADA PEMBUATAN BATAKO Hariningsih, Hariningsih; Pengestu, Adam Yoga; Erlangga, Erlangga
Abdi Teknoyasa Volume 5, No. 2, Desember 2024
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/abditeknoyasa.v5i2.1911

Sekitar 30 industri pengecoran logam di daerah Kecamatan Ceper Klaten masih menggunakan tanur kupola untuk melebur besi cor. Selain besi cair, peleburan besi cor dengan tanur kupola menghasilkan limbah padat yang disebut terak. Limbah terak berbentuk seperti batu namun tajam seperti pecahan kaca dan dapat menyebabkan pencemaran tanah yang mengakibatkan tanah menjadi tidak subur. Sejauh ini terak tersebut hanya digunakan untuk bahan timbunan pada sawah atau kebun, dan terkadang digunakan untuk menimbun jalan. Masalah pembuangan limbah terak ini menjadi masalah tersendiri bagi industri dan masyarakat sekitar. Oleh karena itu masyarakat dan industri perlu dilibatkan dalam penanganan limbah tersebut. Limbah terak dapat dimanfaatkan sebagai agregat kasar pada pembuatan batako. Hasil pengabdian masyarakat berupa produk batako berbahan tambah limbah terak. Selain itu penggunaan limbah terak sebagai agregat kasar pembuatan batako dapat mengurangi jumlah limbah terak di industri, mengurangi polusi tanah, menaikan nilai ekonomis limbah terak, dan dapat menurunkan biaya produksi batako. Capaian peningkatan keterampilan peserta dalam memahami materi pelatihan diukur dengan jenis pendekatan kualitatif cara wawancara. Hasil wawancara menunjukkan tingkat kepuasan yang tinggi dari peserta pelatihan. Peserta sudah memahami dan dapat membuat batako dengan bahan tambah limbah terak secara mandiri.

The Effect of dust on the mechanical properties of greensand molds with new silica sand as the base material: Pengaruh penggunaan debu terhadap sifat mekanik pasir cetak greensand dengan bahan dasar pasir silika baru Hariningsih, Hariningsih; Rizka, Tasha
Perwira Journal of Science & Engineering Vol 5 No 1 (2025)
Publisher : Universitas Perwira Purbalingga

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.54199/pjse.v5i1.483

Debu yang berasal dari dust collector di area cetakan greensand dalam industri pengecoran logam memiliki kadar silika dan lempung yang tinggi. Kandungan ini berasal dari komposisi penyusun pasir cetakan greensand, yaitu bentonit dan pasir silika. Tujuan penelitian ini adalah untuk mengetahui pengaruh penggunaan debu dust colector terhadap sifat mekanik pasir cetak greensand baru, yakni pasir cetak greensand yang menggunakan bahan dasar pasir silika baru, serta mendapatkan presentase penggunaan debu yang tepat untuk mencapai nilai green compressive strength (GCS) yang optimal. Variasi debu yang digunakan adalah 0%, 0,5%, 1% dan 1%. Pengujian pasir yang dilakukan meliputi pengujian compactibility, moisture, permeability, green compression strength (GCS), dry compression strength (DCS), wet tensile strength (WTS). Hasil pengujian menunjukan bahwa kekuatan tekan cetakan meningkat seiring dengan meningkatnya presentase penggunaan debu. Apabila kadar air bertambah, kekuatan tekan dan permeabilitasnya akan betambah atau naik sampai pada titik maksimal. Sedangkan jika kadar airnya bertambah terus maka kekuatan tekan dan permeabilitasnya akan menurun. Penggunaan debu yang optimal pada pasir cetak greensand baru yaitu dengan presentase debu 1%.

PENERAPAN METODE FLAME HARDENING TANPA PROSES TEMPA UNTUK PEMBUATAN PISAU DARI PELAT BAJA SK5 Hariningsih, Hariningsih; Sutiyoko, Sutiyoko; Munadi, Muhammad
Teknika Vol 10 No 1 (2025): April 2025
Publisher : Pusat Penelitian dan Pengabdian Masyarakat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52561/teknika.v10i1.458

Pandai besi biasanya membuat pisau besar dari baja pegas bekas yang ditempa panas. Namun, proses penempaan membutuhkan lebih banyak energi dan peralatan. Selain itu, baja pegas bekas memiliki retakan mikro, deformasi, kelelahan, dan korosi. Tujuan dari penelitian ini adalah untuk mengevaluasi struktur mikro dan kekerasan pisau yang tidak ditempa. Pisau dibuat dari pelat baja karbon kondisi baru (bukan baja bekas) dengan ketebalan 3 mm. Pelat baja dibentuk menggunakan gerinda tangan. Flame hardening pada pisau dilakukan dengan memanaskan baja menggunakan nyala api langsung pada suhu 800-900°C. Tiga jenis media pendingin yang digunakan adalah oli SAE 20W50, oli iso-rapid khusus untuk quenching, dan air dicampur 2,5% NaCl powder. Karakterisasi struktur mikro menggunakan mikroskop optik, dan uji kekerasan menggunakan metode Vickers. Hasil karakterisasi struktur mikro menunjukkan perubahan dari bainit menjadi martensit. Kekerasan tertinggi diperoleh dengan media quenching air dicampur 2,5% NaCl powder, tetapi menyebabkan retakan mikro pada baja. Kekerasannya adalah 810,09 HV pada sisi tebal dan 813,88 HV pada sisi tajam. Hasil terbaik diperoleh dengan oli iso-rapid karena menghasilkan kekerasan tinggi dan tidak menimbulkan retakan. Kekerasannya adalah 723,86 HV pada sisi tebal dan 728,53 HV pada sisi tajam.

Teacher-Parent Collaboration in Managing Hyperactive Children's Behaviors: A Case Study of Inclusive Early Childhood Education Hariningsih, Hariningsih; Mahabbati, Aini
Journal of Innovation and Research in Primary Education Vol. 4 No. 4 (2025)
Publisher : Papanda Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.56916/jirpe.v4i4.2289

Managing hyperactive behaviors in inclusive early childhood settings requires coordinated efforts between educators and families to ensure optimal developmental outcomes. This qualitative case study examined teacher-parent collaboration strategies in addressing hyperactive children's problematic behaviors at an inclusive kindergarten in East Kutai Regency, Indonesia. Data were collected over four months through systematic observations, semi-structured interviews with teachers and parents, and document analysis. Participants included classroom teachers, special needs support staff, and parents of hyperactive children enrolled in class B1. Thematic analysis revealed three primary collaborative dimensions: behavioral recognition through structured communication protocols, participatory assessment procedures involving shared responsibility for instrument development and progress monitoring, and coordinated intervention implementation with regular feedback mechanisms. The findings demonstrate that effective collaboration requires systematic information exchange between home and school environments, with teachers sharing classroom observations while parents provide complementary insights about home-based behavioral patterns. Collaborative assessment procedures enabled comprehensive evaluation extending beyond limited school observation periods, with parents contributing to instrument design and participating in progress reviews. Intervention implementation was characterized by coordinated strategy application across both settings, supported by regular feedback exchanges and periodic evaluation meetings. Despite implementation challenges including time constraints and initial parental resistance to acknowledging children's special needs, the collaborative framework demonstrated effectiveness in managing hyperactive behaviors through sustained partnership efforts. The study contributes a practical model for inclusive early childhood programs, emphasizing the importance of structured collaboration protocols for supporting children with hyperactive behaviors. These findings have implications for educational policy development, teacher training programs, and family support services in inclusive educational settings.

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