Ground Steel Research Articles

Predicting Surface Roughness and Grinding Forces in UNS S34700 Steel Grinding: A Machine Learning and Genetic Algorithm Approach to Coolant Effects

In today’s tech world of digitalization, engineers are leveraging tools such as artificial intelligence for analyzing data in order to enhance their capability in evaluating product quality effectively. This research study adds value by applying algorithms and various machine learning techniques—such as support vector regression, Gaussian process regression, and artificial neural networks—on a dataset related to the grinding process of UNS S34700 steel. What sets this study apart is its consideration of factors like three types of grinding wheels, four distinct cooling solutions, and seven varied depths of cut. These parameters are assessed for their impact on surface roughness and grinding forces, resulting in the conversion of information into insights. A relational equation with 25 coefficients is developed, using optimized algorithms to predict surface roughness with an 85 percent accuracy and grinding forces with a 90 percent accuracy rate. Learning from machine models like the Gaussian process regression exhibited stability, with an R2 value of 0.98 and a mean accuracy of 93 percent. Artificial neural networks achieved an R2 value of 0.96, and an accuracy rate of 90 percent. These findings suggest that machine learning techniques are versatile and precise when dealing with datasets. They align well with digitalization and predictive trends. In conclusion; machine learning provides flexibility and superior accuracy for predicting data trends compared to the formulaic approach, which is contained to existing datasets only. The versatility of machine learning highlights its significance in engineering practices for making data-informed decisions.

Alkaline-washed phosphogypsum-based cemented paste backfill prepared using steel slag and blast furnace slag: mechanical properties, fluoride immobilization, and hydration mechanism

Phosphogypsum (PG)-based cemented paste backfill (PCPB) is an effective way to deal with the problem of PG storage, but the low strength, high cost, and serious fluoride pollution of PCPB limit the popularization of this technology. Alkaline washing has been proven to be an effective means to decrease fluoride from PG. Steel slag (SS) and ground granulated blast furnace slag (GGBFS) are common materials possessing pozzolanic activity. SS and GGBFS can be employed as cement substitutes under alkaline conditions. This paper proposes the combined heuristic effect of NaOH pretreatment, SS, and GGBFS to improve the strength of alkaline-washed PCPB (APCPB) and the ability of fluoride immobilization. The study results show that alkali washing stimulates the secondary hydration activity of solid waste materials and promotes the formation of hydration products such as AFt and C-S-H so that the UCS value of APCPB increases greatly in the later stages of hydration increases by 309.8% (7.06MPa), and the leaching concentration of fluoride decreases by 21.5% (0.85mg/L). Through microscopic characterization experiments on the APCPB, it was discovered that in the alkaline hydration system, the transformation of C-S-H and AFt into C-A-S-H, F-C-S-H, and F-AFm, coupled with the physical encapsulation of hydration products, are the main factors immobilizing fluoride. This work provides a much-needed supplement to the in-situ cement-free repair technology of PG in mines to develop more lower-carbon and environmentally friendly mixture formulations.

Exploring properties and hydration mechanisms in clinker-free cement formulated from steel industry solid waste using the extreme vertices method

The development of clinker-free cementitious binders (CFCB) using industrial solid waste has attracted widespread attention due to their environmental and cost benefits. This study developed a CFCB using ground blast furnace slag (GBFS), steel slag (SS), and flue gas desulfurization gypsum (FGDG) as raw materials, utilizing an extreme vertex design method. The study systematically assessed the effects of each component on the CFCB's properties, hydration behavior, and microstructure, and based on these findings, further elucidated its hydration mechanism using thermodynamic simulations. Results indicated that FGDG played a critical role in regulating the fluidity of the fresh pastes and the compressive strength of the hardened pastes. GBFS enhanced the development of compressive strength, while the high-activity aluminates in SS enhanced the early-stage compressive strength. Thermodynamic simulations and experimental results confirmed that reactive aluminates and sulfates led to the formation of expansive hydration products AFt and AFm, with volume expansion peaking around 10 d. As the hydration reaction progressed, the number of aluminates participating in the reaction gradually increased, promoting the formation of C-A-S-H, hydrogarnet, and hydrotalcite, as well as the transformation of AFt into AFm. Comprehensive analysis suggested that within the GBFS–SS–FGDG system, the proportion of FGDG should not be less than 10 %, the content of GBFS should be controlled between 50 and 57.5 %, and the content of SS should not exceed 37.5 %. This study revealed the hydration mechanisms within the GBFS–SS–FGDG system, emphasizing the critical roles of each component.

Investigation of Effect of Surface Modification by Electropolishing on Tribological Behaviour of Worm Gear Pairs

Electropolishing using a high-current density results in a pitting phenomenon, producing a surface texture distinguished by many pits. Apart from the change in surface topography, electropolishing forms an oxide surface layer characterized by beneficial tribological properties. This paper introduces surface texturing in worm gear pairs by electropolishing a 16MnCr5 steel worm surface. Electropolishing produces surface pits 1 μm to 5 μm deep and 20 to 100 μm in diameter. The material characterization of 16MnCr5 steel is compared against the electropolished 16MnCr5 steel based on microstructure, hardness, surface topography and chemical composition. Experimental tests with worm pairs employing electropolished worms are conducted, and the results are compared to conventional worm pairs with ground steel worms. Electropolished worms show up to 5.2% higher efficiency ratings than ground ones and contribute to better running-in of worm gear pairs. Moreover, electropolished worms can reliably support full contact patterns and prevent scuffing due to improved lubrication conditions resulting from the produced surface texture and oxide surface layer. Based on the obtained results, electropolishing presents a promising method for surface texturing and modification in machine elements characterized by highly loaded non-conformal contacts and complex geometry.

Further Results on the Effects of the Grinding Environment on the Flotation of Copper Sulphides

Grinding conditions affect the flotation of copper sulphide minerals as changes in the properties of the grinding media and their interactions with the sulphide minerals, and between sulphide minerals themselves, affect the chemical environment in the flotation pulp. Galvanic interactions between steel grinding media and sulphide minerals, and between sulphide minerals, can lower the pulp potential, decrease the dissolved oxygen concentration in the mineral slurry, and lead to the dissolution of iron and copper from the media and the minerals. As a result, the formation of hydrophilic iron hydroxides and their adsorption on the copper sulphide minerals can be deleterious to copper flotation while pyrite (when present) can be activated to flotation by dissolved copper lowering the grade of the copper concentrate. Electrochemically less active grinding media (e.g., chrome alloy balls rather than mild steel media) can have beneficial effects on flotation performance due to the lower oxidation of the grinding media and consequently the lower production of oxidised iron species in the pulp. Copper activation of pyrite can be decreased by chemical additions to the pulp. In this paper, relevant experimental data published in the last 15 years are discussed.

Formation of requirements for impact resistance and wear resistance of grinding balls

The article presents the results of a study of the operation processes of steel grinding balls in semi-autogenous grinding mills (SAG). It was determined that the balls experience both abrasive and impact loads. The properties of steel grinding balls with the same production technology are determined by the chemical composition and the formed microstructure over the entire cross-section of the ball. Balls made using 3 different technologies were studied. The balls of sets 1 and 2 show high hardness values at the surface, sufficient to ensure good resistance to wear during operation, and a sharp decrease in hardness at a distance of ~(15–20) mm from the surface as the volume of pearlite structures increases. At the same time, the balls of the 1st and 2nd sets showed low values of impact strength and insufficient resistance to impact. The lowest hardness values from the surface to the center were observed for set 3. Also, the highest mass loss during the abrasive wear test was recorded for set 3, which is explained by the lowest hardness values. The balls of set 3 showed higher values of impact strength and no splitting during the ball-on-ball test, which is explained by the soft ferrite-pearlite structure both on the surface and across the cross section of the ball, due to the reduced carbon content and the presence of nickel in the chemical composition. At the same time, the balls from set 3 showed the worst result in terms of abrasive wear. In the course of the conducted research, it was established that for successful operation in SAG, steel grinding balls must have a surface with high hardness due to the martensitic structure and a viscous core with a ferrite-pearlite structure. A promising direction in the development of technology for the production of steel grinding balls will be to obtain a steel ball microstructure that decreases uniformly from the surface to the center, which will allow maintaining high wear resistance and increasing the resistance to ball splitting

Operations Strategy Formulation to Improve the Operational Capability of Steel Grinding Balls Manufacturer

Operations Strategy Formulation to Improve the Operational Capability of Steel Grinding Balls Manufacturer

Hydration process and fluoride solidification mechanism of multi-source solid waste-based phosphogypsum cemented paste backfill under CaO modification

The large-scale, environmentally friendly utilization of phosphogypsum (PG) remains a global challenge. PG cemented paste backfill (PCPB) is a promising method to manage PG, but using ordinary Portland cement as the binder has drawbacks such as high cost, low mechanical strength, and high fluoride leaching risk. This paper presents a multi-source solid waste-based PCPB (MPCPB) material that enhances mechanical properties and reduces fluoride leaching risks. In MPCPB, industrial waste residues like steel slag (SS) and ground granulated blast furnace slag (GBFS) are used as precursors (SS: GBFS = 1:2). Additionally, 4–8 wt% CaO (relative to the dry weight of PG) is used as a neutralizing modifier and alkaline activator. The results indicate that an optimal amount of CaO can neutralize the residual acidity of PG, provide sufficient Ca(OH)2 for MPCPB hydration, and react with PG to produce significant amounts of AFt. Furthermore, CaO promotes the geopolymerization reaction between SS and GBFS, generating more calcium silicate hydrate (C-S-H) and calcium aluminate silicate hydrate (C-A-S-H) gels. Fluoride stabilization in MPCPB results from synergistic effects involving hydration reactions, complexation, ionic mobility, rearrangement, and physical adsorption. Notably, CaO enhances the conversion of free fluoride ions into stable compounds like fluorapatite, fluorite (CaF2), [AlF6]3-, and [FeF6]3- complexes. This approach offers a cost-effective, environmentally friendly, and efficient solution to the PG stockpiling challenge.

Synthesis of novel composite material with spent coffee ground biochar and steel slag zeolite for enhanced dye and phosphate removal.

Rising concerns over water scarcity, driven by industrialization and urbanization, necessitate the need for innovative solutions for wastewater treatment. This study focuses on developing an eco-friendly and cost-effective biochar-zeolite composite (BZC) adsorbent using waste materials-spent coffee ground biochar (CGB) and steel slag zeolite (SSZ). Initially, the biochar was prepared from spent coffee ground, and zeolite was prepared from steel slag; their co-pyrolysis resulted in novel adsorbent material. Later, the physicochemical characteristics of the BZC were examined, which showed irregular structure and well-defined pores. Dye removal studies were conducted, which indicate that BZC adsorption reach equilibrium in 2h, exhibiting 95% removal efficiency compared to biochar (43.33%) and zeolite (74.58%). Moreover, the removal efficiencies of the novel BZC composite toward dyes methyl orange (MO) and crystal violet (CV) were found to be 97% and 99.53%, respectively. The kinetic studies performed with the dyes and phosphate with an adsorbent dosage of 0.5g L-1 suggest a pseudo-second-order model. Additionally, the reusability study of BZC proves to be effective through multiple adsorption and regeneration cycles. Initially, the phosphate removal remains high but eventually decreases from 92% to 70% in the third regeneration cycle, highlighting the robustness of the BZC. In conclusion, this study introduces a promising, cost-effective novel BZC adsorbent derived from waste materials as a sustainable solution for wastewater treatment. Emphasizing efficiency, reusability, and potential contributions to environmentally conscious water treatment, the findings highlight the composite's significance in addressing key challenges for the removal of toxic pollutants from the aqueous solutions. PRACTITIONER POINTS: A novel biochar-zeolite composite (BZC) material has been synthesized. Excellent removal of dyes by BZC (~95%) was achieved as compared to their counterparts The kinetic studies performed suggest a pseudo-second-order model. BZC proves to be highly effective for multiple adsorption studies. Excellent reusability showed potential as a robust adsorbent.

The Impact of Fly Ash on the Properties of Cementitious Materials Based on Slag-Steel Slag-Gypsum Solid Waste.

This paper presents a novel low-carbon binder formulated from fly ash (FA), ground granulated blast furnace slag, steel slag, and desulfurization gypsum as a quaternary solid waste-based material. It specifically examines the influence of FA content on the mechanical properties and hydration reactions of the quaternary solid waste-based binder. The mortar test results indicate that the optimal FA content is 10%, which yields a 28-day compressive strength 11.28% higher than that of the control group without FA. The spherical particles of fly ash reduce the overall water demand and provide a "lubricating" effect to the paste due to their continuous gradation, improving the fluidity of the slag-steel slag-gypsum cementitious materials. The micro test results indicate that fly ash has minimal effect on the early hydration products and process of the solid waste-based cementitious materials, but after 7 days, it continuously dissolves silicon-oxygen tetrahedrons or aluminum-oxygen tetrahedrons, consuming Ca2+ and OH- in the system. After 28 days, the amount of ettringite and C-(A)-S-H gel generated increases significantly. The pozzolanic activity of fly ash is mainly stimulated by the Ca(OH)2 from steel slag in the later hydration stage. Additionally, spherical fly ash particles can fill the voids in the hardened paste, reducing the formation of cracks and weak zones, and thereby contributing to a denser overall structure of the hydrated binder. The findings of this paper provide data support for the development of low-carbon cement-free binders using fly ash in conjunction with metallurgical slags, thereby contributing to the low-carbon advancement of the construction materials industry.

Quantifying pyrrhotite superstructures in copper-gold ore flotation through synchrotron X-ray diffraction analysis

Pyrrhotite, a significant sulfide mineral in base metal sulfide deposits, exists in various superstructures including magnetic (4C) and non-magnetic (5C and 6C) types. Identifying and quantifying pyrrhotite superstructures in an ore sample has been a challenge, hindering efforts to improve pyrrhotite rejection in copper–gold flotation. This study employed synchrotron X-ray powder diffraction (S-XRPD) analysis to quantify pyrrhotite superstructures in the concentrates obtained from flotation of a copper–gold ore after grinding with forged steel and 30% chromium grinding media. S-XRPD demonstrated a superior capability in detecting characteristic peaks of 4C, 5C and 6C pyrrhotite superstructures compared to conventional XRPD. Utilizing the Rietveld refinement method, the identified pyrrhotite superstructures were quantified. These findings were successfully validated through independent X-ray fluorescence analysis on elemental compositions. The quantification work demonstrated that 30% chromium grinding media enhanced the floatability of all pyrrhotite superstructures over forged steel grinding media and each pyrrhotite superstructure in the copper–gold ore resembled a copper sulfide mineral rather than pyrite in response to grinding media during flotation. This research highlights the potential of S-XRPD as an effective technique for identifying and quantifying pyrrhotite superstructures in ore samples and determining their flotation behaviors.

An Experimental Investigation Replicating the Surface Behavior of Ground Steel Gears in Mixed Lubrication Using Twin-Disk Testing Part 1: Running-in

ABSTRACT The surface of ground gear teeth is changed during the initial period of operation through a process termed running-in. During this process asperity peaks are plastically deformed and removed to better distribute the load across the surface, resulting in modification of the surface finish. In this work the influence of pressure, slide-roll ratio, and entrainment velocity on two-dimensional surface roughness parameters is evaluated through the running-in process using a full-factorial experimental programme. Hardened steel disks are used to simulate gear tooth contacts via the use of a twin-disk rig. Results showed that all three variables strongly influence the change in surface geometry, both individually and through both two- and three-factor interactions.

Understanding the synergistic geopolymerization mechanism of multiple solid wastes in ternary geopolymers

The use of ground granulated blast furnace slag (GBFS), fly ash (FA) and steel slag (SS) to form ternary geopolymers consumes several industrial solid wastes and produces high-performance construction materials. However, the unexplored synergistic geopolymerization mechanism of multiple solid wastes limits the design of high-performance ternary geopolymers. This study investigated the synergistic mechanism through testing the macroscopic performances such as unconfined compressive strength (UCS), final setting time (FST) and fluidity, and characterizing the microscopic structure of ternary geopolymers with different mixture proportions. In addition, the influence of variables on strength development of ternary geopolymers is analyzed by developing machine learning models. Results reveal that the highest strength of ternary geopolymers was achieved at a ratio of FA to GBFS to SS of 3:5:2, and alkali activator to precursor materials of 0.08. Addition of 20 % SS refines the pore network, reducing cumulative and detrimental pore volumes, thus enhancing compressive strength. In addition, the SS addition extends the heat generation peak during geopolymerization due to its slower reaction kinetics. Material components (Na/Al, Si/Al, Ca/Si) have a significant influence on UCS, with Na/Al ratio being the most sensitive variable. The study provides a new approach for utilization of bulk industrial wastes.

Compressive Strength and Resistance to Sulphate Attack of Ground Granulated Blast Furnace Slag, Lithium Slag, and Steel Slag Alkali-Activated Materials

Compressive Strength and Resistance to Sulphate Attack of Ground Granulated Blast Furnace Slag, Lithium Slag, and Steel Slag Alkali-Activated Materials

Numerical simulation of contact surface stress distribution based on stress-magnetization effect surface

Taking the surface profile of C45 steel grinding as the research object, a two-dimensional finite element contact model of rough surface and smooth rigid surface was established by using ANSYS software, and the stress distribution characteristics and rules of contact surface were analyzed under 0–10 MPa normal load. On this basis, the force-magnetic coupling model was established by using ANSYS APDL language. Furthermore, the influence of stress under on leakage magnetic field of contact surface under different load conditions was studied. The results indicated that according to the zero-crossing point of the normal component of the leakage magnetic field or the extreme point of the tangential component, the number of stress concentrations on the contact surface and the stress level of the corresponding area can be effectively determined. This innovative approach offers valuable insights for future studies on surface contact stress distribution between components.

An Experimental Investigation Replicating the Surface Behavior of Ground Steel Gears in Mixed Lubrication Using Twin-Disk Testing Part 2: Micropitting

Tooth surfaces in heavily loaded power-transmission gearing can often suffer from surface fatigue on the surface roughness scale, known as micropitting. In this paper, the influence of three variables (pressure, slide-roll ratio, and entrainment velocity) on micropitting is investigated using a full-factorial experimental program using a twin-disk test rig. The results showed that pressure was most influential on micropitting growth during the latter phases of the test, with slide-roll ratio being a more important factor during micropit initiation. The full-factorial nature of these tests allowed two- and three-factor effects to be investigated, demonstrating that micropitting is a complex phenomenon influenced by a network of interconnected effects.

What Are the Key Factors for the Detection of Peptides Using Mass Spectrometry on Boron-Doped Diamond Surfaces?

We investigated the use of boron-doped diamond (BDD) with different surface morphologies for the enhanced detection of nine different peptides by matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS). For the first time, we compared three different nanostructured BDD film morphologies (Continuous, Nanograss, and Nanotips) with differently terminated surfaces (-H, -O, and -F) to commercially available Ground Steel plates. All these surfaces were evaluated for their effectiveness in detecting the nine different peptides by MALDI-MS. Our results demonstrated that certain nanostructured BDD surfaces exhibited superior performance for the detection of especially hydrophobic peptides (e.g., bradykinin 1-7, substance P, and the renin substrate), with a limit of detection of down to 2.3 pM. Further investigation showed that hydrophobic peptides (e.g., bradykinin 1-7, substance P, and the renin substrate) were effectively detected on hydrogen-terminated BDD surfaces. On the other hand, the highly acidic negatively charged peptide adrenocorticotropic hormone fragment 18-39 was effectively identified on oxygen-/fluorine-terminated BDD surfaces. Furthermore, BDD surfaces reduced sodium adduct contamination significantly.

STUDY ON THE FRICTION AND WEAR PROPERTIES AND SURFACE INTEGRITY OF GCr15 BEARING STEEL UNDER DIFFERENT GRINDING METHODS

In the field of precision machining, there are two widely used grinding methods for the same type of abrasive, namely, fixed abrasive grinding, and free abrasive grinding. In this paper, we utilized a self-developed rolling-sliding ratio controllable friction and wear testing machine to investigate the friction and wear properties of GCr15 bearing steel ground by fixed/free abrasive grinding under rolling and sliding motion, with varying abrasive particle sizes. The surface morphology and roughness of the ground bearing steel were observed and measured using a laser confocal microscope and white light interferometer. Results showed that under rolling and sliding conditions, the coefficient of friction for fixed abrasive grinding was higher than for free abrasive grinding. Under sliding conditions, the grinding efficiency of the fixed abrasive wheel is higher. However, in the case of wheel blockage, the grinding efficiency would significantly decrease. Conversely, the grinding efficiency of free abrasive grinding was observed to be stable throughout the grinding process. Under the same conditions of abrasive particle size in the sliding state, free abrasive grinding showed better surface integrity of bearing steel compared to fixed abrasive grinding.

Properties of Cemented Filling Materials Prepared from Phosphogypsum-Steel Slag-Blast-Furnace Slag and Its Environmental Effect.

Phosphogypsum (PG) occupies a large amount of land due to its large annual production and low utilization rate, and at the same time causes serious environmental problems due to toxic impurities. PG is used for mine backfill, and industrial solid waste is a curing agent for PG, which can save the filling cost and reduce environmental pollution. In this paper, PG was used as a raw material, combined with steel slag (SS) and ground granulated blast-furnace slag (GGBS) under the action of an alkali-activated agent (NaOH) to prepare all-solid waste phosphogypsum-based backfill material (PBM). The effect of the GGBS to SS ratio on the compressive strength and toxic leaching of PBM was investigated. The chemical composition of the raw materials was obtained by XRF analysis, and the mineral composition and morphology of PBM and its stabilization/curing mechanism against heavy metals were analyzed using XRD and SEM-EDS. The results showed that the best performance of PBM was achieved when the contents of PG, GGBS, and SS were 80%, 13%, and 7%, the liquid-to-solid ratio was 0.4, and the mass concentration of NaOH was 4%, with a strength of 2.8 MPa at 28 days. The leaching concentration of fluorine at 7 days met the standard of groundwater class IV (2 mg/L), and the leaching concentration of phosphorus was detected to be less than 0.001 mg/L, and the leaching concentration of heavy metals met the environmental standard at 14 d. The hydration concentration in PBM met the environmental standard. The hydration products in PBM are mainly ettringite and C-(A)-S-H gel, which can effectively stabilize the heavy metals in PG through chemical precipitation, physical adsorption, and encapsulation.

Modification of magnesium phosphate cement with steel slag powder and ground blast furnace slag: Mechanism of hydration and electrical conductivity

This paper delves into the impacts of steel slag powder (SSP) and ground granulated blast furnace slag (GBFS) on the workability, compressive strength, conductivity, and microstructural characteristics of magnesium phosphate cement (MPC). The findings reveal that the incorporation of mineral admixtures ranging from 10 % to 30 % enhances the fluidity of MPC. Despite a slight reduction in the 28d compressive strength of MPC with the inclusion of SSP and GBFS, there is a significant reduction in raw material costs. A notable presence of unreacted MgO, with struvite identified as the principal hydration product. Furthermore, the interaction of SSP, GBFS, and MgO with ADP yielded a dense compound that bolstered the mechanical attributes of MPC. The modified MPC exhibits diminished resistance and markedly enhanced conductivity, suggesting promising applications as an energy storage material. This research introduces an innovative approach to cost reduction in MPC, recycles industrial by-products, and promises to enable the application of MPC in the field of electrode materials for energy storage.