CN102534406B - Medium manganese steel and preparation method thereof - Google Patents
Medium manganese steel and preparation method thereof Download PDFInfo
- Publication number
- CN102534406B CN102534406B CN 201110402660 CN201110402660A CN102534406B CN 102534406 B CN102534406 B CN 102534406B CN 201110402660 CN201110402660 CN 201110402660 CN 201110402660 A CN201110402660 A CN 201110402660A CN 102534406 B CN102534406 B CN 102534406B
- Authority
- CN
- China
- Prior art keywords
- temperature
- manganese steel
- percent
- steel
- controlled
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Heat Treatment Of Articles (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention discloses medium manganese steel. The medium manganese steel comprises the following components in percentage by weight: 0.9 to 1.1 percent of carbon (C), 6 to 8 percent of manganese (Mn), 0.3 to 0.6 percent of silicon (Si), 1.0 to 1.2 percent of chromium (Cr), 0.2 to 0.4 percent of percent (MO), less than or equal to 0.04 percent of phosphorus (P), less than or equal to 0.04 percent of sulphur (S), and the balance of Fe. A preparation method comprises the following steps of: selecting raw materials; smelting, and yielding water after ensuring that the components are qualified, wherein the water yielding temperature is controlled at 1,650 DEG C, and casting; molding, coating after molding, assembling molds and casting; removing sand: cleaning cast burrs, and performing polishing inspection; preserving the heat, stacking casts with sand cleaned in a high-temperature heat treatment furnace, sealing a furnace door, raising the temperature, preserving the heat after the temperature is raised to 1,100 DEG C, preserving the heat for 6 hours, quickly discharging the casts, and putting the casts into water for quenching; and cleaning surfaces again, and inspecting, accepting, warehousing, stacking, classifying and warehousing products. The medium manganese steel has the advantages of ensuring high impact resistance and abrasion resistance of manganese steel; having a simple production process, low production cost and a good market prospect.
Description
[technical field]
The present invention relates to manganese steel and preparation method thereof, specifically relate to a kind of Medium Manganese Steel and preparation method thereof.
[background technology]
Manganese steel is a kind of high-intensity anti-wear resisting steel, is mainly used in withstanding shocks, the bad working environments conditions such as extruding, material wearing and tearing, and collapse mode is take attrition as main, part fracture, distortion.Wearing and tearing are divided into three kinds: the frictional wear that is in contact with one another between metal component surface and moves; The erosive wear that the abrasive wear of other metal or non-metallic material strike metallic surface and flowing gas or liquid and metallic contact cause.The wear resisting property of wear resisting steel depends on material itself, and Development of Wear Resistant Steel then shows different wear resistancies under different working conditions, and material itself and working condition could determine its wear resisting property.Casting wear-resistant steel and Development of Wear Resistant Steel are take Austenitic Manganese Steel as main, and the low alloy steel through appropriate heat treatment also has good effect under certain conditions, and graphitized steel then is used for the working condition of lubrication friction.
Antiwear high manganese steel is specially adapted to impact abrasive wear and the heavily stressed abrasive wear operating mode of pulverizing, be usually used in making ball grinding machine lining board, hammer head of hammer crusher, jaw plate of jaw crusher, cone crusher rolled mortar wall, crushing wall, excavator bucket teeth, headwall, railroad turnout, the shock resistances such as grip-pad of tractor and tank, wear-resistant foundry goods.High mangaenese steel also is used for: armour plate, safety locker steel plate etc.High mangaenese steel is typical Development of Wear Resistant Steel, and as-cast structure is that austenite adds carbide.Structural transformation is that single austenite or austenite adds a small amount of carbide after 1000 ℃ of left and right sides Water Quenching, and toughness improves on the contrary, therefore claims water tough processing.
The tough processing of water is the point-device technique of technical height, technique and parameter request, and maximum heating temperature and the ratio between the alloying element in the high mangaenese steel in the tough processing of water are closely bound up.
Because existing high mangaenese steel and steel alloy shock resistance and wear resisting property are undesirable, cause its in use loss higher, in order further to improve high mangaenese steel shock resistance and wear resistance, seek to be applicable to the new steel grade under the different industrial and minerals, the researchist of various countries has made a series of research in composition and the proportioning of the alloying element of high mangaenese steel in recent years.
[summary of the invention]
One of technical problem to be solved by this invention is to provide a kind of shock resistance and the good Medium Manganese Steel of wear resistance.
Two of technical problem to be solved by this invention is the preparation method of above-mentioned Medium Manganese Steel.
The present invention is what one of to solve the problems of the technologies described above by the following technical programs: a kind of Medium Manganese Steel is comprised of following compositions in weight percentage: carbon (C): 0.9～1.1%; Manganese (Mn): 6～8%; Silicon (Si): 0.3～0.6%; Chromium (Cr): 1.0～1.2%; Molybdenum (MO): 0.2～0.4%; Phosphorus (P): less than or equal to 0.08%; Sulphur (S): less than or equal to 0.08%; All the other are iron.
Preferably: carbon (C): 0.95～1.1%; Manganese (Mn): 7.2～7.8%; Silicon (Si): 0.4～0.5%; Chromium (Cr): 1.05～1.15%; Molybdenum (MO): 0.2～0.3%; Phosphorus (P): less than or equal to 0.05%; Sulphur (S): less than or equal to 0.05%; All the other are iron.
Best proportioning is: carbon (C): 1.1%; Manganese (Mn): 7.5%; Silicon (Si): 0.45%; Chromium (Cr): 1.1%; Molybdenum (MO): 0.3%; Phosphorus (P): 0.04%; Sulphur (S): 0.04%; All the other are iron.
The present invention be solve the problems of the technologies described above by the following technical programs two: a kind of preparation method of Medium Manganese Steel may further comprise the steps:
Step 1: at first select preferably waste and old manganese steel and steel scrap as raw material;
Step 2: smelt, above-mentioned waste and old manganese steel is become manganese steel water with steel scrap by Dian Lu Rong, and add alloying element and carry out the composition adjustment, the qualified rear ability water outlet of assurance composition, leaving water temperature(LWT) is controlled at 1650 ℃ and pours into a mould, and its composition is controlled at:
Carbon (C): 0.9～1.1%; Manganese (Mn): 6～8%; Silicon (Si): 0.3～0.6%; Chromium (Cr): 1.0～1.2%; Molybdenum (MO): 0.2～0.4%; Phosphorus (P): less than or equal to 0.08%; Sulphur (S): less than or equal to 0.08%; All the other are iron;
Step 3: moulding, select high-quality basic material sand as moulding sand, after making, coats by type, carry out again mould assembling, cast, teeming temperature is controlled at 1480 ℃, and then thermal treatment holding temperature is 1050 ℃, and soaking time is 4 hours;
Step 4: sand removal, behind the casting complete, control the sand removal time according to the foundry goods size;
Step 5: cleaning hard edges, polishing check;
Step 6: thermal treatment, the foundry goods of clear good sand is deposited in the high-temperature heat treatment stove puts well, seal fire door, heat up, temperature is incubated after being raised to 1100 ℃, is incubated 6 hours;
Step 7: quench, fast foundry goods is come out of the stove, tapping temperature is controlled at 980 ℃, immerses in the diesel oil medium that is in the normal temperature state to carry out disposable quenching in 10～15 minutes, and quenching process medium casting temperature is controlled at 900 ℃～950 ℃;
Step 8: again clear up surface and product and carry out an acceptance inspection, advance storehouse, stacking, classification warehouse-in.
In the described step 2, preferred: carbon (C): 0.95～1.1%; Manganese (Mn): 7.2～7.8%; Silicon (Si): 0.4～0.5%; Chromium (Cr): 1.05～1.15%; Molybdenum (MO): 0.2～0.3%; Phosphorus (P): less than or equal to 0.05%; Sulphur (S): less than or equal to 0.05%; All the other are iron.
In the described step 2, best proportioning is: carbon (C): 1.1%; Manganese (Mn): 7.5%; Silicon (Si): 0.45%; Chromium (Cr): 1.1%; Molybdenum (MO): 0.3%; Phosphorus (P): 0.04%; Sulphur (S): 0.04%; All the other are iron.
In the described step 4,40-60mm thickness was unpacked at 6 hours, the more unpacking sand removal in above 8 hours of 80mm thickness.
In the described step 7, during quenching light casting temperature drift is controlled at 925 ℃～950 ℃, and casting temperature is on the low side greatly is controlled at 900 ℃～925 ℃.
Advantage of the present invention is:
1, each the alloying element ratio in this manganese steel is reasonable, and particularly the ratio of crucial alloying element manganese, carbon is reasonable, has guaranteed shock resistance and the wear resistance of manganese steel; This manganese steel yield strength can reach 395～410MPa, and tensile strength can reach 600～630MPa, and unit elongation can reach 33～38%, shrinking percentage can reach 35～37%, impact toughness can reach 185～190J, and hardness of cast form can reach 240～250HB, and processing intensity can reach 480～495HB.
2, the properties of this manganese steel can be used in structure comparatively simple, require take wear-resisting as main low impact foundry goods, such as liner plate, tooth plate, roller shell, teeth etc., saved material under the prerequisite of performance requriements reaching, reduced production cost.
3, the perfect tough treatment process of water particularly passes through repetition test, has provided best maximum heating temperature, and the relation between the ratio of this maximum heating temperature and each alloying element is closely bound up.
Leaving water temperature(LWT) when 4, adjusting composition also is repeatedly to prove, the critical point temperature that draws.
5, in the alloying element of this Medium Manganese Steel, do not contain noble metal alloy, and under the prerequisite that obtains the shock resistance identical or close with existing manganese steel and wear resistance, this production technique is simpler, production cost is low, therefore has good market outlook.
[embodiment]
The invention will be further described below in conjunction with embodiment, can be implemented so that those skilled in the art can better understand the present invention also, but illustrated embodiment is not as a limitation of the invention.
Medium Manganese Steel of the present invention is comprised of following compositions in weight percentage: carbon (C): 0.9～1.1%; Manganese (Mn): 6～8%; Silicon (Si): 0.3～0.6%; Chromium (Cr): 1.0～1.2%; Molybdenum (MO): 0.2～0.4%; Phosphorus (P): less than or equal to 0.08%; Sulphur (S): less than or equal to 0.08%; All the other are iron.
Preferably: carbon (C): 0.95～1.1%; Manganese (Mn): 7.2～7.8%; Silicon (Si): 0.4～0.5%; Chromium (Cr): 1.05～1.15%; Molybdenum (MO): 0.2～0.3%; Phosphorus (P): less than or equal to 0.05%; Sulphur (S): less than or equal to 0.05%; All the other are iron.
Best proportioning is: carbon (C): 1.1%; Manganese (Mn): 7.5%; Silicon (Si): 0.45%; Chromium (Cr): 1.1%; Molybdenum (MO): 0.3%; Phosphorus (P): 0.04%; Sulphur (S): 0.04%; All the other are iron.
The preparation method of above-mentioned Medium Manganese Steel may further comprise the steps:
Step 1: at first select preferably waste and old manganese steel and steel scrap as raw material;
Step 2: smelt, above-mentioned waste and old manganese steel is become manganese steel water with steel scrap by Dian Lu Rong, and add alloying element and carry out the composition adjustment, the qualified rear ability water outlet of assurance composition, leaving water temperature(LWT) is controlled at 1650 ℃ and pours into a mould, and its composition is controlled at:
Carbon (C): 0.9～1.1%; Manganese (Mn): 6～8%; Silicon (Si): 0.3～0.6%; Chromium (Cr): 1.0～1.2%; Molybdenum (MO): 0.2～0.4%; Phosphorus (P): less than or equal to 0.08%; Sulphur (S): less than or equal to 0.08%; All the other are iron.
Preferably: carbon (C): 0.95～1.1%; Manganese (Mn): 7.2～7.8%; Silicon (Si): 0.4～0.5%; Chromium (Cr): 1.05～1.15%; Molybdenum (MO): 0.2～0.3%; Phosphorus (P): less than or equal to 0.05%; Sulphur (S): less than or equal to 0.05%; All the other are iron.
Best proportioning is: carbon (C): 1.1%; Manganese (Mn): 7.5%; Silicon (Si): 0.45%; Chromium (Cr): 1.1%; Molybdenum (MO): 0.3%; Phosphorus (P): 0.04%; Sulphur (S): 0.04%; All the other are iron.
Step 3: moulding, select high-quality basic material sand as moulding sand, after making, coats by type, carry out again mould assembling, cast, teeming temperature is controlled at 1480 ℃, and then thermal treatment holding temperature is 1050 ℃, and soaking time is 4 hours;
Step 4: sand removal, behind the casting complete, control the sand removal time according to the foundry goods size;
Step 5: cleaning hard edges, polishing check;
Step 6: thermal treatment, the foundry goods of clear good sand is deposited in the high-temperature heat treatment stove puts well, seal fire door, heat up, temperature is incubated after being raised to 1100 ℃, is incubated 6 hours;
Step 7: quench, fast foundry goods is come out of the stove, tapping temperature is controlled at 980 ℃, immerses in the diesel oil medium that is in the normal temperature state to carry out disposable quenching in 10～15 minutes, and quenching process medium casting temperature is controlled at 900 ℃～950 ℃; Wherein, during quenching light casting temperature drift is controlled at 925 ℃～950 ℃, and casting temperature is on the low side greatly is controlled at 900 ℃～925 ℃.
Step 8: again clear up surface and product and carry out an acceptance inspection, advance storehouse, stacking, classification warehouse-in.
In the above-mentioned steps, the production process such as smelting, moulding, sand removal, cleaning, thermal treatment and existing manganese steel are produced similar, and key point is time and the temperature of control technique.
Medium Manganese Steel of the present invention is compared with the manganese steel that present conventional formulation and production technique are produced, and has excellent comprehensive mechanical property and use properties, shown in particular case sees the following form:
| Index (mean value) | Hardness behind the mill | Impelling strength (J/cm2) | Tensile strength (N/mm2) | Work-ing life |
| Tradition high mangaenese steel | HV≤450 | ≥90 | ＞800 | ～6 months |
| The tradition medium carbon alloy steel | HV560～610 | ≥15 | ＞900 | ～9 months |
| Medium Manganese Steel of the present invention | HV≥680 | ≥70 | ≥1000 | ～12 months |
As can be seen from the above table, Medium Manganese Steel of the present invention had both had certain impelling strength, had again hardness behind the good mill, used through reality to show, high mangaenese steel and medium carbon alloy steel that the work-ing life of Medium Manganese Steel of the present invention is more traditional have improved more than 50%～100%.
Although more than described the specific embodiment of the present invention; but being familiar with those skilled in the art is to be understood that; our described specific embodiment is illustrative; rather than for the restriction to scope of the present invention; those of ordinary skill in the art are in modification and the variation of the equivalence of doing according to spirit of the present invention, all should be encompassed in the scope that claim of the present invention protects.
Claims (5)
1. the preparation method of a Medium Manganese Steel is characterized in that: may further comprise the steps:
Step 1: at first select preferably waste and old manganese steel and steel scrap as raw material;
Step 2: smelt, above-mentioned waste and old manganese steel and steel scrap are melt into manganese steel water by electric furnace, and add alloying element and carry out the composition adjustment, guarantee that composition is qualified just to tap afterwards, tapping temperature is controlled at 1650 ℃ and pours into a mould, and its composition is controlled at:
Carbon (C): 0.9～1.1%; Manganese (Mn): 6～8%; Silicon (Si): 0.3～0.6%; Chromium (Cr): 1.0～1.2%; Molybdenum (Mo): 0.2～0.4%; Phosphorus (P): less than or equal to 0.08%; Sulphur (S): less than or equal to 0.08%; All the other are iron;
Step 3: moulding, select high-quality basic material sand as moulding sand, after making, coats by type, carry out again mould assembling, cast, teeming temperature is controlled at 1480 ℃, and then controlling holding temperature is 1050 ℃, and soaking time is 4 hours;
Step 4: sand removal, behind the casting complete, control the sand removal time according to the foundry goods size;
Step 5: cleaning hard edges, polishing check;
Step 6: thermal treatment, the foundry goods of clear good sand is deposited in the high-temperature heat treatment stove puts well, seal fire door, heat up, temperature is incubated after being raised to 1100 ℃, is incubated 6 hours;
Step 7: quench, fast foundry goods is come out of the stove, tapping temperature is controlled at 980 ℃, immerses in the diesel oil medium that is in the normal temperature state to carry out disposable quenching in 10～15 minutes, and quenching process medium casting temperature is controlled at 900 ℃～950 ℃;
Step 8: again clear up surface and product and carry out an acceptance inspection, advance storehouse, stacking, classification warehouse-in.
2. the preparation method of Medium Manganese Steel as claimed in claim 1 is characterized in that: in the described step 2, preferred: carbon (C): 0.95～1.1%; Manganese (Mn): 7.2～7.8%; Silicon (Si): 0.4～0.5%; Chromium (Cr): 1.05～1.15%; Molybdenum (Mo): 0.2～0.3%; Phosphorus (P): less than or equal to 0.05%; Sulphur (S): less than or equal to 0.05%; All the other are iron.
3. the preparation method of Medium Manganese Steel as claimed in claim 1, it is characterized in that: in the described step 2, best proportioning is: carbon (C): 1.1%; Manganese (Mn): 7.5%; Silicon (Si): 0.45%; Chromium (Cr): 1.1%; Molybdenum (Mo): 0.3%; Phosphorus (P): 0.04%; Sulphur (S): 0.04%; All the other are iron.
4. the preparation method of Medium Manganese Steel as claimed in claim 1 is characterized in that: in the described step 4,40-60mm thickness was unpacked at 6 hours, the sand removal of unpacking again in above 8 hours of 80mm thickness.
5. the preparation method of Medium Manganese Steel as claimed in claim 1, it is characterized in that: during quenching light casting temperature drift is controlled at 925 ℃～950 ℃, and it is large that casting temperature is on the low side is controlled at 900 ℃～925 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110402660 CN102534406B (en) | 2011-12-07 | 2011-12-07 | Medium manganese steel and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110402660 CN102534406B (en) | 2011-12-07 | 2011-12-07 | Medium manganese steel and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN102534406A CN102534406A (en) | 2012-07-04 |
| CN102534406B true CN102534406B (en) | 2013-09-18 |
Family
ID=46342420
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201110402660 Expired - Fee Related CN102534406B (en) | 2011-12-07 | 2011-12-07 | Medium manganese steel and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102534406B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103667917A (en) * | 2013-11-08 | 2014-03-26 | 铜陵安东铸钢有限责任公司 | High-temperature-resistant low-carbon steel material and preparation method thereof |
| CN103789704B (en) * | 2014-01-25 | 2015-12-02 | 安徽省临泉县智创精机有限公司 | A kind of high-ductility alloy steel and preparation method thereof |
| CN104372256A (en) * | 2014-10-24 | 2015-02-25 | 无锡兆一锻压数控装备有限公司 | Special crane boom material for electric shovel and processing method of special crane boom |
| CN105112793A (en) * | 2015-08-10 | 2015-12-02 | 霍邱县忠振耐磨材料有限公司 | Medium manganese steel jaw plate for small- and medium-sized jaw crusher and manufacturing method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN86107760A (en) * | 1986-11-10 | 1988-07-06 | 机械工业部哈尔滨焊接研究所 | Weldable wearproof casting medium manganese steel |
| CN1150980A (en) * | 1995-11-17 | 1997-06-04 | 王宇辉 | Medium manganese austenite abrasion-resistant cast steel |
| CN101423884A (en) * | 2008-12-09 | 2009-05-06 | 徐信 | Method for producing high-manganses wear resistant steel plate and steel plate produced thereby |
-
2011
- 2011-12-07 CN CN 201110402660 patent/CN102534406B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN86107760A (en) * | 1986-11-10 | 1988-07-06 | 机械工业部哈尔滨焊接研究所 | Weldable wearproof casting medium manganese steel |
| CN1150980A (en) * | 1995-11-17 | 1997-06-04 | 王宇辉 | Medium manganese austenite abrasion-resistant cast steel |
| CN101423884A (en) * | 2008-12-09 | 2009-05-06 | 徐信 | Method for producing high-manganses wear resistant steel plate and steel plate produced thereby |
Non-Patent Citations (4)
| Title |
|---|
| 中锰钢齿板及其在使用中的加工硬化问题;李梅溪等;《上海金属》;19880930;第10卷(第5期);第23-29页 * |
| 刘鼎胜等.加铬中锰钢衬板的生产实践.《铸造技术》.2011,(第4期),第589-590页. |
| 加铬中锰钢衬板的生产实践;刘鼎胜等;《铸造技术》;20110418(第4期);第589-590页 * |
| 李梅溪等.中锰钢齿板及其在使用中的加工硬化问题.《上海金属》.1988,第10卷(第5期),第23-29页. |
Also Published As
| Publication number | Publication date |
|---|---|
| CN102534406A (en) | 2012-07-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102534405B (en) | High manganese steel and preparation method thereof | |
| CN100519804C (en) | High chromium abrasion-proof cast iron abrasive disc and manufacturing method thereof | |
| CN102134682B (en) | Wear resistant steel plate | |
| CN101455986B (en) | Crusher duplex metal abrasion-proof backing block and manufacture method thereof | |
| CN101476090B (en) | High-temperature wear resistant kilneye cap iron alloy and manufacturing method thereof | |
| CN103451546A (en) | High-wear-resisting high-manganese steel and preparation method thereof | |
| CN102242314A (en) | Multiple alloy toughened and wear-resistant middle-manganese steel and preparation technology thereof | |
| CN104164609A (en) | Compound hammerhead of hammer crusher | |
| CN102534404B (en) | Super-high manganese steel and manufacturing method thereof | |
| CN102310014B (en) | High performance composite metal hammer | |
| CN102230142A (en) | High manganese steel with ultra-high strength, high impact resistance and high abrasion resistance | |
| CN102115850A (en) | Multi-component low-alloyed large-scale wear-resistant cast steel hammerhead and preparation process thereof | |
| CN105316567A (en) | Abrasion-resistant lining plate for cone crusher | |
| CN102534406B (en) | Medium manganese steel and preparation method thereof | |
| CN102634734A (en) | Wear-resistant hammer head for crusher and production method thereof | |
| CN104328334A (en) | High wear resistance high chromium cast iron used for bimetallic composite tube and preparation method thereof | |
| CN101100724A (en) | Hammer head material for annular hammer coal breaker | |
| CN102978518B (en) | Rare earth wear-resisting alloy steel and production method thereof | |
| CN104004973A (en) | Steel balls of coal mill, and preparation process and loading grading application method thereof | |
| CN101555570B (en) | High-chromium-nickel quinary alloy casting and production process thereof | |
| CN104988378A (en) | Mold special for ductile iron grinding balls and manufacturing technology of mold | |
| CN101555573A (en) | Alloy steel and heat treatment method thereof | |
| CN108914021A (en) | A kind of anti-abrasive wear alloy of Fe-Cr-B-C and preparation method thereof | |
| CN103343290A (en) | High-manganese steel and preparation method thereof | |
| CN111304546A (en) | Super-strength wear-resistant alloy and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130918 Termination date: 20141207 |
|
| EXPY | Termination of patent right or utility model |