Passive Zone Research Articles

A rare case of downward progressive failure in eastern Canada: the 1976 Saint-Fabien landslide

The Saint-Fabien landslide occurred in December 1976, 270 km northeast of Quebec City, Canada. The landslide took place in a valley filled with glaciomarine sensitive clay covered by peat bog deposits and presenting an upwards hydraulic gradient. Unique features of this event are the ground surface and the failure surface that are both close to the horizontal. In addition, passive and active failure zones were observed in the debris after the landslide, indicating a possible downward progressive failure mechanism, rarely observed in Eastern Canadian clays. Possible triggers of the event are: the continuous exploitation of the peat downslope and (or) the roadworks going on along Road 132 at the time of the event, which is crossing the landslide area upslope. Conventional stability analysis for the site gives a factor of safety of 1.43, indicating that limit equilibrium analysis cannot explain the formation of the failure surface observed at Saint-Fabien. The initiation and the propagation of the failure were analysed through 1D numerical modelling using the concept of progressive failure. The methodology consists of two steps: first the calculation of the initial stresses in the slope with the finite element software PLAXIS 2D; and second, the modelling of initiation and propagation of the progressive failure along the potential failure surface with the finite element code BIFURC, developed at the Norwegian Geotechnical Institute. Results from the modelling with BIFURC show that the concept of progressive failure is able to explain the extent of the landslide observed at Saint-Fabien with parameter values based on what was measured in situ.

Pitting corrosion induced on high-strength high carbon steel wire in high alkaline deaerated chloride electrolyte

Abstract Electrochemical response causing pitting corrosion of high-strength high carbon steel wire in deaerated electrolyte at pH 13.4 due to different chloride ion (Cl−) concentrations was investigated using open circuit potential, cyclic potentiodynamic polarization, and anodic potentiostatic application (APA) within the passive zone. Results showed that the higher the Cl− concentration, the more negative the corrosion potential becomes. In the high alkaline pH 13.4 without the presence of free oxygen gas the Cl− concentration could reach up to 1 M not showing pitting potential. An inverse relationship between anodic potentials (APs) and Cl− concentrations was found and the rate of corrosion within passive period was almost a constant, not influenced by the Cl− concentrations. Faraday´s law failed to predict the mass loss when active pitting corrosion occurred. Green rust and hydrogen gas were observed during active pitting corrosion under APA. Pitting corrosion mechanism in the deaerated high alkaline electrolyte was then proposed. This work deduces that in the deaerated electrolyte at pH 13.4 with the presence of Cl−, it is essential to apply the APs within the safety margin on the high-strength high carbon steel wire to avoid active pitting corrosion and hydrogen embrittlement.

Studying the Effect of Butanol on the Anode Behavior of Copper in Phosphoric Acid Solutions

The anode behavior of the copper electrode immersed in butanol phosphate electrolytes has been studied. The polarization dependences of the electrode allowed us to detect the sections that correspond to the passive and active states of copper and we also established the zone of the combined behavior of the processes of the copper dissolution and oxygen release. It was also established that a butyl alcohol contributes to an abrupt decrease in current densities in the entire region of anode potentials. The addition of butanol conditions the disappearance of current oscillations that can be seen on polarization dependences in phosphate solutions. Evidently, a decrease in the current densities is a consequence of the butanol adsorption on the copper surface and its participation in the formation of passive films. The specific features of the copper passivation in butanol phosphate electrolytes are characterized by the appearance of the explicit current peak that separates active and passive state zones at the ratio of C4H9OН:H3PO4 =1:3.As the alcohol-to-acid ratio increases, the peak gradually decreases. The addition of butanol has no determining influence on the potential value that corresponds to the started oxygen release. Currentefficiency values for the copper dissolution depend on the anode current density ja and the electrolyte composition. An increase in ja results in a decreased current efficiency value. An increase in the С4Н9ОН content has a similar action. Maximum current efficiency values are observed at ja=0.5–2 А∙dm-2, and they correspond to the active copper state. The dependences obtained for the copper dissolution rate allowed us to establish that υрalso increases with an increase in the current density up to ja=20 А∙dm-2. The copper treatment quality depends on the current density and the electrolyte composition. The solutions with the ratio of C4H9OН:H3PO4=2:1fail to provide a high quality treatment; the surface is not glossy and it has grinding traces. A high-quality treatment is observed in the electrolytes with the ratio of C4H9OН:H3PO4 =1:2 and lower. The electrochemical polishing in such solutions results in the glossy copper surface with the smoothed relief and it has no polishing traces.

Corrosion Behavior of Steels in LiBr–H2O–CaCl2–LiNO3 Systems

Conventional absorption and refrigeration systems use a LiBr/H2O mixture, which causes corrosion problems to the metallic components. In order to avoid this and some other problems such as crystallization and vapor pressure, some additives such as CaCl2 and/or LiNO3 are added to the LiBr/H2O mixture. In the present work, the corrosion behavior of 1018 carbon steel as well as of type 304 and 316L stainless steels was evaluated in LiBr/H2O at 80 °C with the addition of CaCl2, LiNO3, and CaCl2+LiNO3. Potentiodynamic polarization curves and electrochemical impedance spectroscopy were used for this purpose. The results showed that the corrosion current density values of all tested steels decreased with the addition of CaCl2 and/or LiNO3, which induced the formation of a passive film on carbon steel. Both types of stainless steels showed a passive film in all tested conditions, but the passive current density was the lowest, whereas the passive zone was the widest, for 316L steel. The corrosion mechanism remained unaltered for both stainless steels but was changed with the addition of CaCl2 and/or LiNO3 for carbon steel.

Failure mode and mechanism of large cylinder structures for artificial islands on soft clay

The large cylinder structures as the retaining structure for artificial islands, are crucial in mega sea-crossing infrastructure projects (such as the Hong Kong-Zhuhai-Macao Bridge project). As the structure is mainly embedded in sand or rock with a small embedment depth previously, the stability of large cylinder structures deeply embedded in soft clay remains unclear. Thus, this study explores the failure mode and ultimate load of such structure in thick, soft clays through experimentation and examines the effect of the sand compaction piles used to reinforce the soft clay. The results demonstrate that the sliding failure mode controls the stability of the large cylinder structure in soft clay and the slip surface consists of three parts in the soil: the active zone, the structure zone, and the passive zone. Moreover, the sand compaction piles can effectively raise the ultimate load of the structure when its replacement area ratio reaches 30%. The ultimate load of the structure also enlarges with increasing the embedment depth of the sand compaction piles. This study sheds light on the design of large cylinders as a retaining structure for artificial island.

Microstructure and corrosion behavior of Al95-x Ni x Y5 (x = 7,10) glassy ribbons.

In this work, we correlate the microstructure and passivation of the Al95−xNixY5 lightweight glassy ribbons (x = 7 and 10) using various techniques. The overdosed Ni (x = 10) can increase the melt viscosity and then deteriorate its glass-forming ability (GFA), ribbon formability, and Y-depleted extra layer formation. Consequently, the overdosed Ni weakens the passivation stability and corrosion resistance of the as-spun ribbon. The key role of the overdosed Ni can form a strong network and crystalline grain boundary in the amorphous matrix, which can transport Y and O to participate in the oxidation. These results can help us explore a valuable method for designing new Al-based metallic glasses.

High wear resistance and better pitting corrosion resistance of AISI 316L stainless steel by a self-protective oxy-nitrocarburizing paste

Simultaneous oxidation and nitrocarburizing of AISI 316 SS at 580 °C for 5, 10, 15, and 20 min were studied using self-protecting pastes of sodium cyanate and sodium carbonate. The analytical techniques of XRD and SEM/EDS allowed the characterization of surface modifications. The corrosion resistance was evaluated in a synthetic seawater solution using the cyclic potentiodynamic polarization technique. The cross-section hardness and wear resistance were assessed by Vickers indentation and pin-on-disc, respectively. This thermochemical process formed an oxidized compound layer above a solid nitrogen solution in austenite. The compound layer was composed of intermixed crystals of Fe3O4, ε-Fe3N, and expanded austenite. With increasing relative proportions of the first two phases and decreasing relative proportions of the third phase with increasing treatment time. The balance between the expanded austenite and the chemical composition of the compound layer improved the hardness, the wear-resistant, and the pitting corrosion resistance of the AISI 316L SS surface simultaneously. Oxy-nitrocarburizing at 580 °C for 10 min allowed the best-localized corrosion resistance. However, the sample oxy-nitrocarburized for 20 min reached a more stable passive zone with the highest wear resistance. Self-protective pastes based on sodium cyanates and carbonates allowed the oxy-nitrocarburizing process to consume less salt than the traditional molten salts.

Effect of melt superheating treatment on corrosion resistance of Al2CoCrCuFeNi high entropy alloy in 0.5 M HNO3 solution

Al2CoCrCuFeNi high-entropy alloy (HEA) was heated by vacuum arc furnace at different powers (5.26kW, 6.15 kW, 7.28 kW, 8.26 kW) to different temperatures above the liquidus point (labeled as T1, T2, T3 and T4). The structure and corrosion resistance were investigated by means of X-ray diffraction, scanning electron microscopy with spectroscopy (SEM/EDS), transmission electron microscopy (TEM), and electrochemical workstation. It was found that the HEAs with different superheating temperatures were all simple face-centered cubic (FCC) and body-centered cubic (BCC) solid solutions without complex phases. As the superheating temperature increased, the structure of HEAs became dense, the segregation decreased, and some fine-scale precipitations were formed at T4. When the heating temperature reached T3 or higher, the corrosion current density of the alloy decreased by more than 1/2, and the range of the passivation zone also became wider, indicating that the corrosion resistance was significantly improved. It was found that the pitting potential Eb ranked: T1<T2<T4<T3, indicating that the alloys labeled as T3 and T4 had better pitting resistance than those labeled as T1 and T2. The potential range of the stable passivation region △E ranked: T1<T2<T3<T4, which proved that the passivation film on the surface of HEA became more and more stable as the superheating temperature increased.

Evaluation of Non-Isothermal Kinetic Parameters for Pyrolysis of Teak Wood using Model-Fitting Techniques

Teak wood is one of the prominently used raw material in the construction industry, thus contributing extremely to the biomass waste available in Nigeria. These wastes are usually used for energy generation that requires upgrade into better fuel before application. Hence, the present study evaluates the non-isothermal kinetic parameters for pyrolysis of teak wood using model-fitting techniques. Teak wood dust was subjected to proximate, ultimate and calorific value analyses based on different ASTM standards. The thermal degradation and decomposition behaviour of the teak wood dust was examined using a thermogravimetric analyzer. Pulverized teak (6.5 mg) was heated from 30 to 800 ºC at varying heating rates (5, 10 and 15 ºC) in an environment where 100 mL/min of nitrogen gas was charged in continuously to maintain an inert condition. Avrami-Erofeev, Ginstling-Broushtein (GB) and Mampel models were used to evaluate the kinetic parameters of the pyrolysis of teak wood dust. The teak wood dust contained 7.25 % moisture, 79.26 % volatile matter (VM), 1.74 % ash and 11.75 % fixed carbon. The calorific value of the wood dust was 18.72 MJ/kg. The results of the thermogravimetric analyses depicted that heating rate has no effect on weight loss during the reactive drying zone. However, as the thermal treatment progressed into the active pyrolysis and passive pyrolysis zones, the weight loss decreased with increase in heating rate. The devolatilization parameters also increased with heating rates except for the maximum conversion. The results of the kinetic parameters evaluation revealed that the GB model was best fit to evaluate the kinetic parameters of teak in the active pyrolysis zone while GB and Mampel models were considered most appropriate for the evaluation of the kinetic parameters in the passive pyrolysis zone. Model-fitting method has the capacity to capture a wide range of fractional conversion at a glance.&#x0D; HIGHLIGHTS&#x0D; &#x0D; Arrhenius parameters in terms of activation energy and pre-exponential factor for the pyrolysis of teak wood while comparing 4 different model-fitting techniques were obtained&#x0D; The α-temperature plot for solid state reaction of teak wood dust was a bell-shape (sigmoidal model)&#x0D; The Avrami-Erofeev and SSS models were unable to capture the overlapping multiple reactions that took place simultaneously at the active pyrolysis zone&#x0D; Higher energy input is needed for devolatilization of teak wood dust to give 10 - 80 % conversion due to higher activation energy at the active pyrolysis zone&#x0D; Ginstling-Broushtein was found to be the best model for evaluating the kinetic parameters at the active pyrolysis zone as it had the highest R2 value&#x0D; &#x0D; GRAPHICAL ABSTRACT

Influence of nutrition on Cu corrosion by Desulfovibrio vulgaris in anaerobic environment

The eutrophication of seawater is not only harmful to the environment, but also influence microbes’ proliferation and then influence biocorrosion of marine engineering materials to a great extent. This study investigated the microbiologically influenced corrosion (MIC) of Cu immersed in the Desulfovibrio vulgaris (a sulfate reducing bacterium) medium with four defined nutritional degrees: total nutrition, P lacking, N lacking, and P&N lacking. When D. vulgaris was cultured in more nutritional medium, more H2S was generated and more serious corrosion of Cu occurred. The concentration of H2S corresponding to the medium with total nutrition was as high as 4.9 × 104(±913.0) ppm. The weight loss of Cu in medium with total nutrition increased by at least 50% compared with other nutritional conditions. The depth of pitting pits on Cu increased obviously with more abundant nutrient elements N and P. The electrochemical tests supported the weight loss and also showed that an obvious passivation zone was formed on the anodic polarization curve. This indicated that a protective film was formed on the surface of Cu against uniform corrosion. The analyses of thermodynamics and experiment data indicated that metabolite MIC (M-MIC) account for the Cu corrosion by D. vulgaris.

Effect of Freeze Pipe Eccentricity in Selective Artificial Ground Freezing Applications

Abstract Building concentric tubes is one of biggest practical challenges in the construction of freeze-pipes of selective artificial ground freezing (S-AGF) applications for underground mines. In this study, the influence of tubes eccentricity on phase-front expansion (i.e., expansion of the frozen body) and energy consumption of S-AGF systems is analyzed. A 1 + 1D semi-conjugate model that solves two-phase transient energy conservation equation is derived based on the enthalpy method. The 1 + 1D model is first validated against experimental data and then verified with a fully conjugate model from our previous work. After that, the 1 + 1D model is extended to a field-scale of typical underground mines to examine the effect of freeze-pipe eccentricity. The results show that concentric freeze-pipes form the desired frozen ground volume 17% faster than eccentric freeze-pipes. Also, the geometrical profile of the phase-transition front of the frozen ground is found to be significantly influenced by the freeze-pipe eccentricity. Furthermore, in the passive zone, where S-AGF coolants are isolated from the ground to reduce energy consumption, freeze-pipe eccentricity can increase the coolant heat gain by 20%. This percentage can increase up to 200% if radiation heat transfer is minimized.

Effect of Cu segregation on the phase transformation and properties of AlCrFeNiTiCux high-entropy alloys

In this work, the effect of Cu on the phase transformation, microstructure, and properties of AlCrFeNiTiCux high-entropy alloys (HEAs) was investigated. Meanwhile, the formation mechanism of the FCC solid solution was discussed. The results showed that it was a beneficial effect on the formation of the FCC solid solution for the addition of Cu into HEAs from the perspective of valence electron concentration (VEC), enthalpy of mixing (ΔHmix) and difference in atom size (δ), which was confirmed by X-ray diffraction and Scanning Electron Microscope analysis. In addition, the increment of Cu content in the alloys promoting the segregation of Al, Ni and Ti in dendrite and Fe, Cr segregated into particles distributed in dendrite and inter-dendrite. The micro-hardness of the HEAs decreased with increasing Cu content and as the Cu content increased, oxidative wear intensified. However, the friction coefficient was significantly reduced, which was related to the lubricity of Cu itself. Besides, the segregation of Cu increased the corrosion current density of the passivation zone of the HEAs, thereby reducing the corrosion resistance of the HEAs in 0.5 mol/L H2SO4 solution.

Microstructure and corrosion behaviour of 316 L-IN625 functionally graded materials via laser metal deposition

In this work, the microstructure of gradient regions and the corrosion behaviour of transition interfaces for 316 L-IN625 functional graded materials fabricated using laser metal deposition are investigated. The microstructure in gradient regions along the build direction such as celluar dendrites, columnar grains, coarse dendrites, and nearly equiaxed grains. When the composition of 316 L is less than or equal to 40%, the over passivation zone appears, resulting in the Mixed Cr (III/VI) oxide as the final corrosion products which consists of surviving Cr (III) oxide and generated Cr (VI) oxide. The composition gradient of 316 L-IN625 can effectively improve the corrosion resistance.

Numerical Simulation Research on Mandrel reaming of Ring Steel Ingot

The mandrel reaming forging is of great significance to the billeting of the ring ingot. Through the analysis of the reaming deformation of the ring steel ingot mandrel, it is concluded that the ring steel ingot reaming deformation exists in the radial, axial and tangential directions, which are similar to the rigid zone, active plastic deformation zone and passive plastic deformation zone in the upsetting theory. Numerical simulation methods are used to analyze the reaming of the ring steel ingot mandrel, and it is verified that the ring steel ingot reaming deformation has a rigid zone, an active plastic deformation zone and a passive plastic deformation zone in the radial, axial and tangential directions. At the same time, the reduction rate is found has a greater impact on the three regions.

FEASIBILITY STUDY OF JALUPANG WASTE DISPOSAL SITE OF SUBANG REGENCY

The increasing number of residents in Subang Regency every year has a direct impact on the amount of waste generation that must be managed. Until now, Subang Regency only has the Panembong Waste Disposal Site (WDS) in Parung Village which is intended to serve the entire Subang Regency area which includes 30 sub-districts. The Panembong TPA has started operating Since 1991, with the current Open Dumping operational system, the Panembong TPA has experienced an overload on an active land area of ​​± 2.2 Ha. The total area of ​​the Panembong TPA is ± 6.5 Ha which is used ± 1.6 Ha for general landfill infrastructure, the Active Zone of ± 2.2 Ha is used as a landfill area and the Passive Zone ± 2.7 With such conditions, the Subang Regency government proposes and plans to transfer and move the location of the Final Waste Disposal Site (TPA) at the planned location, while the planning location for this TPA is at: Jalupang Village, Kalijati District. The new TPA is planned to use the Sanitary Landfill system, considering that the Open Dumping system is no longer allowed by the government since 2009 which is based on Law No. 18 of 2008 concerning Waste Management. The initial step in the construction of the Sanitary Landfill TPA system is determining the location of the TPA which must comply with the requirements and provisions regarding environmental management, public order, city/environment cleanliness, regional regulations on waste management and urban spatial planning, as well as other implementing regulations that have been determined. by the government. To be able to determine the location of the landfill that meets these requirements.

Low-Temperature Plasma Nitriding of 3Cr13 Steel Accelerated by Rare-Earth Block

The plasma nitriding of 3Cr13 steel occurred at 450 °C for 4, 8 and 12 h in NH3 with and without rare earth (RE). The nitrided layers were characterized using an OM, SEM, TEM, XRD, XPS, microhardness tester and electrochemical workstation. The modified layer, with and without La, are composed of a compound layer and diffusion layer from surface to core. After the addition of La during nitriding, the maximum increase of layer thickness, mass gain and average microhardness was 15.6%, 35.8% and 212.50HV0.05, respectively. With the increase of the proportion of ε-Fe2-3N, the passivation zone of the corrosion resistance curve increases from 2.436 to 3.969 V, the corrosion current density decreases, the corrosion potential and pitting potential both increase, and, consequently, the corrosion resistance is significantly improved. Most of the surface microstructures of the nitrided layer was refined by the addition of La. The presence of La reduces the N content in the modified layer, which accelerates the diffusion of N atoms and, thus, accelerates the nitriding process.

Co-design: Tactile Models and Prototype as Common Language Tools between Designers and Visually Impaired People

This article presents the use of tactile models and prototype as common language tools among designers, blind and visually impaired (B&VI), inserted in a collaborative design methodology. With the objective of realizing an interior architecture project and an outdoor area, including toys, for an association for visually impaired people in the city of Passo Fundo, RS, Brazil. It describes the process of participation and interaction between Association members, both adults and children, and architects in the development of these projects. It shows results of two co-design actions, which will subsidize a broader objective of a research that aims to define co-design methods, techniques and tools applied to the inclusion of Visually Impaired People in the process of architecture, urbanism, landscaping and interior design. The research related two co-design. The first is the co-design of the waiting / reception room and the external area for socializing and leisure, carried out with the adults of the association, took place in three moments: in the focus group, in the interaction with the tactile model and on the tours accompanied. The second co-design was carried out with the children of the association to develop two toys, the first to be inserted within the proposal of improving reception/ waiting, and the second for placement in the outdoor area of socializing and leisure. The interaction among designers, blind and visually impaired was intensive, allowing modifications and diverse insights about types of floors, layout and better and adequate colors for the best comfort and mobility inside the spaces. It seeks to demonstrate the importance of co-design as a way of including B&VI, as they are able to increase well-being and self-esteem, while effectively participating in the creation of the environment in which they are inserted; they manage to leave the passive zone that they normally find themselves in with regard to the architectural design process. The next steps of the research are to finalize the toy design of the external area and the execution of all spaces.

Surface Morphological and Chemical Features of Anticorrosion ZrO2–TiO2 Coatings: Impact of Zirconium Precursor

Dense, highly textured, hydrophobic ZrO2-TiO2 (1:1) coatings with amorphous structure were prepared using the sol-gel method. Both organic and inorganic zirconium precursor salts were used. The present study dealt with the investigation of their protective ability in a selected model corrosive medium with chloride ions as corrosion activators. The coatings showed good anticorrosion performance during the test, which was demonstrated both by the weight loss method and potentiodynamic polarization curves. The samples were characterized by means of X-ray diffraction (XRD), Atomic Force Microscopy (AFM), contact angle measurements, Infrared spectroscopy (IRS), Scanning Electron Microscopy (SEM), Differential Thermal analysis (DTA-TG) and X-ray photoelectron spectroscopy (XPS). It was established that the extent of influence of some factors, like treatment temperature (Ttr) and type of zirconium precursor, was different. The PD curves of samples treated at 400 °C (A4 and B4, respectively) demonstrated an increased effect of the precursor in comparison to Ttr, since the application of organic Zr salt led to deterioration of the anodic passivation zones. Contrary to this, the coatings obtained from both the organic and inorganic Zr precursor salts with Ttr = 500 °C had similar corrosion efficiency, i.e., the influence of the precursor was minimized. All investigated coatings had no visible corrosion damage. It seems that some complex structural and surface parameters, such as amorphous dense structure, surface smoothness, hydrophobicity and the surface chemical composition (low hydroxyl groups content), were responsible for the increased anticorrosion properties of the composite films.

Crustal Structure of the Nile Delta: Interpretation of Seismic-Constrained Satellite-Based Gravity Data

Interpretations of the tectonic setting of the Nile Delta of Egypt and its offshore extension are challenged by the thick sedimentary cover that conceals the underlying structures and by the paucity of deep seismic data and boreholes. A crustal thickness model, constrained by available seismic and geological data, was constructed for the Nile Delta by inversion of satellite gravity data (GOCO06s), and a two-dimensional (2D) forward density model was generated along the Delta’s entire length. Modelling results reveal the following: (1) the Nile Delta is formed of two distinctive crustal units: the Southern Delta Block (SDB) and the Northern Delta Basin (NDB) separated by a hinge zone, a feature widely reported from passive margin settings; (2) the SDB is characterized by an east–west-trending low-gravity (~−40 mGal) anomaly indicative of continental crust characteristics (depth to Moho (DTM): 36–38 km); (3) the NDB and its offshore extension are characterized by high gravity anomalies (hinge zone: ~10 mGal; Delta shore line: &gt;40 mGal; south Herodotus Basin: ~140 mGal) that are here attributed to crustal thinning and stretching and decrease in DTM, which is ~35 km at the hinge zone, 30–32 km at the shoreline, and 22–20 km south of the Herodotus Basin; and (4) an apparent continuation of the east-northeast–west-southwest transitional crust of the Nile Delta towards the north-northeast–south-southwest-trending Levant margin in the east. These observations together with the reported extensional tectonics along the hinge zone, NDB and its offshore, the low to moderate seismic activity, and the absence of volcanic eruptions in the Nile Delta are all consistent with the NDB being a non-volcanic passive margin transition zone between the North African continental crust (SDB) and the Mediterranean oceanic crust (Herodotus Basin), with the NDB representing a westward extension of the Levant margin extensional transition zone.

On a precision forming criterion for groove-section profiled ring rolling process

For the groove-section profiled ring rolling (GSPRR) of difficult-to-deform materials, one of the most challenging issues is to ensure the precision forming of ring groove before the diameter reaches to the desired value. The deformation behavior and mechanism of the GSPRR has been clarified in this work. It is found that the pulling effect of the active deformation zone on the passive deformation zone, quantificationally described by a pulling coefficient introduced in this paper, plays a decisive role in the precision forming of ring groove. The smaller the pulling coefficient, the weaker the pulling effect. This leads to less metal flowing in the circumferential direction for diameter growth, thus more metal flowing into the main roll cavity for the groove forming. The influences of the dimensions of the target rolled ring, rectangular blank thickness and processing parameters on the pulling coefficient are revealed. And a regression model describing the relationship between the pulling coefficient and its key influencing factors is developed. Based on the pulling coefficient model, a precision forming criterion for the GSPRR is established, by which a critical value of the rectangular blank thickness ensuring the precision forming of ring groove can be determined. The critical value is related to the rectangular blank thickness and the structural dimensions of the target rolled ring such as the relative groove height, so the developed criterion can provide an important guidance to design the blank and the target rolled ring (forging drawing) for the GSPRR process.